(Slip Opinion)              OCTOBER TERM, 2009                                       1

                                       Syllabus

         NOTE: Where it is feasible, a syllabus (headnote) will be released, as is
       being done in connection with this case, at the time the opinion is issued.
       The syllabus constitutes no part of the opinion of the Court but has been
       prepared by the Reporter of Decisions for the convenience of the reader.
       See United States v. Detroit Timber & Lumber Co., 200 U. S. 321, 337.


SUPREME COURT OF THE UNITED STATES

                                       Syllabus

             ALABAMA ET AL. v. NORTH CAROLINA

ON EXCEPTIONS TO THE PRELIMINARY AND SECOND REPORTS
               OF THE SPECIAL MASTER

    No. 132, Orig. Argued January 11, 2010—Decided June 1, 2010
In 1986, Congress granted its consent to the Southeast Interstate Low-
  Level Radioactive Waste Management Compact (Compact), which
  was entered into by Alabama, Florida, Georgia, Mississippi, North
  Carolina, South Carolina, Tennessee, and Virginia. The Compact is
  administered by a Commission, which was required, inter alia, to
  “identif[y] a host State for the development of a [new] regional
  disposal facility,” and to “seek to ensure that such facility is licensed
  and ready to operate . . . no . . . later than 1991.” Art. 4(E)(6), 99
  Stat. 1875. The Commission designated North Carolina as a host
  State in 1986, thereby obligating North Carolina to take “appropriate
  steps to ensure that an application for a license to construct and op
  erate a [low-level radioactive waste storage facility] is filed with and
  issued by the appropriate authority.” Art. 5(C), id., at 1877.
     In 1988, North Carolina asked the Commission for assistance with
  the costs of licensing and building a facility. The Commission
  adopted a resolution declaring it “appropriate and necessary” to pro
  vide financial assistance, and ultimately paid almost $80 million to
  North Carolina from 1988 through 1997. North Carolina also ex
  pended $34 million of its own funds. Yet by the mid 1990s, North
  Carolina was still many years—and many tens of millions of dol
  lars—away from obtaining a license.
     In 1997, the Commission notified North Carolina that absent a
  plan for funding the remaining licensing steps, it would not disburse
  additional funds to North Carolina. North Carolina responded that it
  could not continue without additional funding. After the parties
  failed to agree on a long-term financing plan, in December 1997 the
  Commission ceased its financial assistance to North Carolina, and
  North Carolina subsequently began an orderly shutdown of its pro
2                   ALABAMA v. NORTH CAROLINA

                                 Syllabus

    ject.
       In June 1999, Florida and Tennessee filed a complaint with the
    Commission seeking monetary sanctions against North Carolina. In
    July 1999, North Carolina exercised its right under Article 7(G) to
    withdraw from the Compact. In December 1999, the Commission
    concluded that North Carolina had failed to fulfill its obligations un
    der the Compact and adopted a sanctions resolution demanding that
    the State repay approximately $80 million in addition to other mone
    tary penalties. North Carolina did not comply.
       In 2003, this Court granted Alabama, Florida, Tennessee, Virginia,
    and the Commission (Plaintiffs) leave to file a bill of complaint
    against North Carolina under this Court’s original jurisdiction, U. S.
    Const., Art. II, §2, cl. 2; 28 U. S. C. §1251(a). The complaint sets
    forth claims of violation of Plaintiffs’ rights under the Compact
    (Count I), breach of contract (Count II), unjust enrichment (Count
    III), promissory estoppel (Count IV), and money had and received
    (Count V), and requests monetary and other relief, including a decla
    ration that North Carolina is subject to sanctions and that the Com
    mission’s sanctions resolution is valid and enforceable.
       The Court assigned the case to a Special Master, who has con
    ducted proceedings and has filed two reports. The Preliminary Re
    port recommends denying without prejudice North Carolina’s motion
    to dismiss the Commission’s claims on sovereign immunity grounds;
    denying Plaintiffs’ motion for summary judgment on Count I, which
    sought enforcement of the Commission’s sanctions resolution; grant
    ing North Carolina’s cross-motion to dismiss Count I and other por
    tions of the complaint seeking such enforcement; and denying North
    Carolina’s motion to dismiss the claims in Counts II–V. The Master’s
    Second Report recommended denying Plaintiff’s motion for summary
    judgment and granting North Carolina’s motion for summary judg
    ment on Count II; and denying North Carolina’s motion for summary
    judgment on Plaintiffs’ remaining claims in Counts III–V. The par
    ties filed a total of nine exceptions to the Master’s Reports.
Held:
    1. Plaintiffs’ seven exceptions are overruled. Pp. 7–21.
       (a) The terms of the Compact do not authorize the Commission to
 impose monetary sanctions against North Carolina. The Court’s con
 clusion is confirmed by a comparison of the Compact’s terms with
 three other interstate compacts concerning low-level radioactive
 waste storage approved by Congress contemporaneously with the
 Compact, all of which expressly authorize their commissions to im
 pose monetary sanctions against their party States. Pp. 7–9.
       (b) Plaintiffs’ exception that North Carolina could not avoid
 monetary sanctions by withdrawing from the Compact is moot, be
                   Cite as: 560 U. S. ____ (2010)                    3

                              Syllabus

cause the Compact does not permit the Commission to impose mone
tary sanctions in any event. The Court deems their exception that
North Carolina forfeited its right to object to a monetary penalty by
failing to participate at the sanctions hearing both abandoned and
meritless. P. 10.
      (c) Because the express terms of the Compact do not make the
Commission the “sole arbiter” of disputes arising under the Compact,
Texas v. New Mexico, 462 U. S. 554, 569–570, the Court is not bound
by the Commission’s conclusion that North Carolina breached its ob
ligations under the Compact. Nor does the Court apply deferential
administrative-law standards of review to the Commission’s conclu
sion, but instead exercises its independent judgment as to both fact
and law in executing its role as the “exclusive” arbiter of controver
sies between the States, 28 U. S. C. §1251(a). Pp. 10–12.
      (d) North Carolina did not breach its contractual obligation to
take “appropriate steps” toward the issuance of a license. Pp. 12–19.
         (1) The Compact requires North Carolina to take only those li
censing steps that are “appropriate.” The parties’ course of perform
ance establishes that it was not appropriate for North Carolina to
proceed with the very expensive licensing process without external
financial assistance. Nothing in the Compact’s text or structure re
quires North Carolina to cover all licensing and building costs on its
own. Plaintiffs’ assertion that it was understood that the host State
would bear the up-front licensing and construction costs, but recoup
those costs through its regional monopoly on radioactive waste dis
posal, is not reflected in the Compact. Pp. 13–18.
         (2) Plaintiffs’ alternative argument that North Carolina repu
diated its obligation to take appropriate steps when it announced it
would take no further steps to obtain a license fails for the same rea
sons their breach theory fails. Pp. 18–19.
      (e) North Carolina did not breach an implied duty of good faith
and fair dealing when it withdrew from the Compact. The Compact
by its terms imposes no limitation on North Carolina’s right to exer
cise its statutory right under Article 7(G) to withdraw from the Com
pact. A comparison between the Compact and other contemporane
ously enacted compacts confirms the absence of a good-faith
limitation in the Compact. Pp. 19–21.
   2. North Carolina’s two exceptions are overruled. Pp. 21–26.
      (a) It was reasonable for the Special Master to deny without
prejudice North Carolina’s motion for summary judgment on the mer
its of Plaintiffs’ equitable claims in Counts III–V. The Special Master
concluded that those claims require further briefing, argument, and,
possibly, discovery. The Court approves of the Special Master’s rea
sonable exercise of his discretion to manage the proceedings. Pp. 21–
4                   ALABAMA v. NORTH CAROLINA

                                 Syllabus

    22.
         (b) Under Arizona v. California, 460 U. S. 605, 614, the Commis
    sion’s claims are not barred by sovereign immunity so long as the
    Commission asserts the same claims and seeks the same relief as the
    plaintiff States. Nothing in the Court’s subsequent cases suggests
    that Arizona v. California has been implicitly overruled, and North
    Carolina does not ask the Court to overrule that decision. At least
    with respect to Counts I and II, the Commission’s claims under those
    Compact-related Counts are wholly derivative of the plaintiff States’
    claims. The summary judgment disallowing the claims in Counts I
    and II on their merits renders the sovereign immunity question with
    regard to any relief the Commission alone might have on those claims
    moot. Counts III–V are on a different footing. The Special Master
    concluded that further factual and legal development was necessary
    to determine whether the Commission’s claims under these Counts
    were identical to those of the plaintiff States. The Special Master’s
    case-management decision was reasonable. Pp. 22–26.
Exceptions to Special Master’s Reports overruled, and Master’s recom
  mendations adopted; North Carolina’s motions to dismiss Count I
  and for summary judgment on Count II granted; Plaintiffs’ motions
  for judgment on Counts I and II denied; and North Carolina’s mo
  tions to dismiss the Commission’s claims on sovereign immunity
  grounds and for summary judgment on Counts III–V denied without
  prejudice.

   SCALIA, J., delivered the opinion of the Court, in which STEVENS,
GINSBURG, and ALITO, JJ., joined, in which ROBERTS, C. J., joined in all
but Parts II–D and III–B, in which KENNEDY and SOTOMAYOR, JJ.,
joined in all but Part II–E, in which THOMAS, J., joined in all but Part
III–B, and in which BREYER, J., joined in all but Parts II–C, II–D, and
II–E. KENNEDY, J., filed an opinion concurring in part and concurring
in the judgment, in which SOTOMAYOR, J., joined. ROBERTS, C. J., filed
an opinion concurring in part and dissenting in part, in which THOMAS,
J., joined. BREYER, J., filed an opinion concurring in part and dissent
ing in part, in which ROBERTS, C. J., joined.
                        Cite as: 560 U. S. ____ (2010)                              1

                             Opinion of the Court

     NOTICE: This opinion is subject to formal revision before publication in the
     preliminary print of the United States Reports. Readers are requested to
     notify the Reporter of Decisions, Supreme Court of the United States, Wash­
     ington, D. C. 20543, of any typographical or other formal errors, in order
     that corrections may be made before the preliminary print goes to press.


SUPREME COURT OF THE UNITED STATES
                                   _________________

                                  No. 132, Orig.
                                   _________________


STATE OF ALABAMA, STATE OF FLORIDA, STATE OF

 TENNESSEE, COMMONWEALTH OF VIRGINIA, AND

  SOUTHEAST INTERSTATE LOW-LEVEL RADIO- 

   ACTIVE WASTE MANAGEMENT COMMISSION, 

    PLAINTIFFS v. STATE OF NORTH CAROLINA

ON EXCEPTIONS TO THE PRELIMINARY AND SECOND REPORTS
               OF THE SPECIAL MASTER
                                 [June 1, 2010]

  JUSTICE SCALIA delivered the opinion of the Court.
  In this case, which arises under our original jurisdiction,
U. S. Const., Art. III, §2, cl. 2; 28 U. S. C. §1251(a), we
consider nine exceptions submitted by the parties to two
reports filed by the Special Master.
                             I
   In 1986, Congress granted its consent under the Com­
pact Clause, U. S. Const., Art. I, §10, cl. 3, to seven inter­
state compacts providing for the creation of regional facili­
ties to dispose of low-level radioactive waste. Omnibus
Low-Level Radioactive Waste Interstate Compact Consent
Act, 99 Stat. 1859. One of those compacts was the South­
east Interstate Low-Level Radioactive Waste Management
Compact (Compact), entered into by Alabama, Florida,
Georgia, Mississippi, North Carolina, South Carolina,
Tennessee, and Virginia. Id., at 1871–1880. That Com­
pact established an “instrument and framework for a
cooperative effort” to develop new facilities for the long­
2              ALABAMA v. NORTH CAROLINA

                      Opinion of the Court

term disposal of low-level radioactive waste generated
within the region. Art. 1, id., at 1872. The Compact was
to be administered by a Southeast Interstate Low-Level
Radioactive Waste Management Commission (Commis­
sion), composed of two voting members from each party
State. Art. 4(A), id., at 1874.
   A pre-existing facility in Barnwell, South Carolina was
to serve as the initial facility for regional generators to
dispose of their low-level radioactive waste. Art. 2(10), id.,
at 1873. That facility was scheduled to close as the re­
gional-disposal facility for the Compact by the end of 1992,
ibid., and so the Compact required the Commission to
develop “procedures and criteria for identifying . . . a host
[S]tate for the development of a second regional disposal
facility,” and to “seek to ensure that such facility is li­
censed and ready to operate as soon as required but in no
event later than 1991,” Art. 4(E)(6), id., at 1875. The
Compact authorized the Commission to “designate” a
party State as a host State for the facility. Art. 4(E)(7),
ibid.
   In September 1986, the Commission designated North
Carolina as the host for the second facility. North Caro­
lina therefore became obligated to “take appropriate steps
to ensure that an application for a license to construct and
operate a [low-level radioactive waste storage facility] is
filed with and issued by the appropriate authority.” Art.
5(C), id., at 1877. In 1987, North Carolina’s General
Assembly created the North Carolina Low-Level Radioac­
tive Waste Management Authority (Authority) to fulfill
the State’s obligation. N. C. Gen. Stat. §104G (1987), 1987
N. C. Sess. Laws ch. 850.
   Although “[t]he Commission is not responsible for any
costs associated with,” among other things, “the creation of
any facility,” Art. 4(K)(1), 99 Stat. 1876, North Carolina
asked the Commission for financial assistance with build­
ing and licensing costs. The Commission responded by
                 Cite as: 560 U. S. ____ (2010)           3

                     Opinion of the Court

adopting a resolution, which declared it was both “appro­
priate and necessary” for the Commission “to provide
financial assistance” to North Carolina. App. 63. To that
end, the Commission created a “Host States Assistance
Fund” to help North Carolina with the “financial costs and
burdens” of “preliminary planning, the administrative
preparation, and other pre-operational” activities. Id., at
64.
   The estimate in 1989 was that it would cost approxi­
mately $21 million and take two years to obtain a license
for North Carolina’s regional-disposal facility.      That
proved to be wildly optimistic. By 1990, the cost estimate
had ballooned to $45.8 million, and the estimated date for
obtaining a license now extended far into 1993. At the
beginning of 1994 there still was no license, and the esti­
mated cost had grown to $87.1 million. By end of 1994 the
estimate was $112.5 million, and issuance of a license was
not anticipated until 1997. And by December 1996 the
estimated cost had increased by another $27 million and
the projected date to receive a license had become August
2000.
   North Carolina’s own appropriations—approximately
$27 million from Fiscal Year 1988 through Fiscal Year
(FY) 1995—did not cover the costs of the licensing phase.
But during the same time period, the Commission pro­
vided North Carolina with approximately $67 million.
The funds came from surcharges and access fees collected
for that purpose from generators disposing of low-level
radioactive waste at the pre-existing Barnwell facility.
Id., at 71–74, 145.
   In July 1995, however, South Carolina withdrew from
the Compact, thereby depriving the Commission of contin­
ued revenues from the Barnwell facility. In 1996, the
Commission accordingly informed North Carolina that it
would no longer be able to provide financial support for
licensing activities. The Governor of North Carolina
4              ALABAMA v. NORTH CAROLINA

                     Opinion of the Court

responded that the State was not prepared to assume a
greater portion of the project’s costs, and would not be able
to proceed without continued Commission funding.
Shortly thereafter the Commission adopted a resolution
declaring that it was willing and able to provide additional
funds, but calling on North Carolina to work with it to
develop long-term funding sources for the facility. From
FY 1996 through FY 1998, the Commission provided
North Carolina approximately an additional $12.27 mil­
lion in financial assistance. North Carolina, for its part,
continued to provide its own funds toward licensing activi­
ties—another $6 million during the same time period.
   In August 1997, the Commission notified North Caro­
lina that absent a plan for funding the remaining steps of
the licensing phase, it would not disburse additional funds
to North Carolina after November 30, 1997. North Caro­
lina responded that it would not be able to continue with­
out additional guarantees of external funding. On Decem­
ber 1, 1997, the parties having failed to agree upon a long­
term financing plan, the Commission ceased financial
assistance to North Carolina. By then it had provided
almost $80 million.
   On December 19, 1997, North Carolina informed the
Commission it would commence an orderly shutdown of its
licensing project, and since that date has taken no further
steps toward obtaining a license for the facility. But it did
continue to fund the Authority for several more years, in
the hope that the project would resume upon the restora­
tion of external financial assistance. North Carolina
maintained the proposed facility site, preserved the work
it had completed to date, and retained the Authority’s
books and records. It also participated in discussions with
the Commission, generators of low-level radioactive waste,
and other stakeholders regarding options to resolve the
financing shortfall. From FY 1988 through FY 2000,
North Carolina had expended almost $34 million toward
                 Cite as: 560 U. S. ____ (2010)            5

                     Opinion of the Court

obtaining a license.
   In June 1999, after attempts to resolve the funding
impasse had failed, Florida and Tennessee filed with the
Commission a complaint for sanctions against North
Carolina. It alleged that North Carolina had failed to
fulfill its obligations under the Compact, and requested
(among other things) return of the almost $80 million paid
to North Carolina by the Commission, plus interest, as
well as damages and attorney’s fees. The next month,
North Carolina withdrew from the Compact by enacting a
law repealing its status as a party State, see 1999 N. C.
Sess. Laws ch. 357, as required by Article 7(G) of the
Compact.
   More than four months later, in December 1999, the
Commission held a sanctions hearing. North Carolina did
not participate. After the hearing, the Commission con­
cluded that North Carolina had failed to fulfill its obliga­
tions under the Compact. It adopted a resolution demand­
ing that North Carolina repay approximately $80 million,
plus interest, to the Commission; pay an additional $10
million penalty to compensate the Commission for the loss
of future revenue (surcharges and access fees) it would
have received had a facility been completed in North
Carolina; and pay the Commission’s attorney’s fees. North
Carolina did not comply.
   In July 2000, seeking to enforce its sanctions resolution,
the Commission moved for leave to file a bill of complaint
under our original jurisdiction. Southeast Interstate Low-
Level Radioactive Waste Management Commission v.
North Carolina, No. 131, Orig. North Carolina opposed
the motion on the grounds that the Commission could not
invoke this Court’s original jurisdiction, and we invited
the Solicitor General to express the views of the United
States. 531 U. S. 942 (2000). The Solicitor General filed a
brief urging denial of the Commission’s motion on the
grounds that the Commission’s bill of complaint did not
6              ALABAMA v. NORTH CAROLINA

                     Opinion of the Court

fall within our exclusive original jurisdiction over “contro­
versies between two or more States.” §1251(a). We denied
the Commission’s motion. 533 U. S. 926 (2001).
   In June 2002, the States of Alabama, Florida, Tennes­
see, and Virginia, joined by the Commission (collectively
Plaintiffs), moved for leave to file a bill of complaint
against North Carolina. North Carolina opposed the
motion, and we again sought the views of the Solicitor
General. 537 U. S. 806 (2002). The United States urged
that we grant Plaintiffs’ motion, which we did. 539 U. S.
925 (2003). The bill of complaint contains five counts:
violation of the party States’ rights under the Compact
(Count I); breach of contract (Count II); unjust enrichment
(Count III), promissory estoppel (Count IV); and money
had and received (Count V). Plaintiffs’ prayer for relief
requests a declaration that North Carolina is subject to
sanctions and that the Commission’s sanctions resolution
is valid and enforceable, as well as the award of damages,
costs, and other relief.
   We assigned the case to a Special Master, 540 U. S.
1014 (2003), who has conducted proceedings and now has
filed two reports. The Master’s Preliminary Report ad­
dressed three motions filed by the parties. He recom­
mended denying without prejudice North Carolina’s mo­
tion to dismiss the Commission’s claims against North
Carolina on the grounds of sovereign immunity. Prelimi­
nary Report 4–14. He recommended denying Plaintiffs’
motion for summary judgment on Count I, which sought
enforcement of the Commission’s sanctions resolution. Id.,
at 14–33. He recommended granting North Carolina’s
cross-motion to dismiss Count I and other portions of the
bill of complaint that sought enforcement of the sanctions
resolution. Id., at 33–34. And he recommended denying
North Carolina’s motion to dismiss the claims in Counts
II–V. Id., at 34–43.
   After the Special Master issued his Preliminary Report,
                  Cite as: 560 U. S. ____ (2010)             7

                      Opinion of the Court

the parties engaged in partial discovery and subsequently
filed cross-motions for summary judgment. The Special
Master’s Second Report recommended denying Plaintiffs’
motion for summary judgment on Count II, Second Report
8–35, and granting North Carolina’s motion for summary
judgment on Count II, id., at 35–40. Finally, he recom­
mended denying North Carolina’s motion for summary
judgment on Plaintiffs’ remaining claims in Counts III–V.
Id., at 41–45.
                            II
  Plaintiffs present a total of seven exceptions to the
Special Master’s two reports. We address them in turn.
                                A
   Their first exception challenges the Special Master’s
conclusion that the Commission lacked authority to im­
pose monetary sanctions upon North Carolina. The terms
of the Compact determine that question.
   Article 4(E) of the Compact sets forth the Commission’s
“duties and powers.” Among its powers are the authority
“[t]o revoke the membership of a party [S]tate that will­
fully creates barriers to the siting of a needed regional
facility,” Art. 4(E)(7), 99 Stat. 1875, and the authority “[t]o
revoke the membership of a party [S]tate in accordance
with Article 7(f),” Art. 4(E)(11), ibid. Conspicuously ab­
sent from Article 4, however, is any mention of the author­
ity to impose monetary sanctions. Plaintiffs contend that
authority may be found elsewhere—in the first paragraph
of Article 7(F), which provides in relevant part:
      “Any party [S]tate which fails to comply with the
    provisions of this compact or to fulfill the obligations
    incurred by becoming a party [S]tate to this compact
    may be subject to sanctions by the Commission, in­
    cluding suspension of its rights under this compact
    and revocation of its status as a party [S]tate.” Id., at
8              ALABAMA v. NORTH CAROLINA

                     Opinion of the Court

    1879.
The sanctions expressly identified in Article 7(F)—
“suspension” of rights and “revocation” of party-state
status—flow directly from the Commission’s power in
Articles 4(E)(7) and (11) to revoke a party State’s member­
ship. That can fairly be understood to include the lesser
power to suspend a party State’s rights. There is no simi­
lar grounding in Article 4(E) of authority to impose mone­
tary sanctions, and the absence is significant.
   According to Plaintiffs, however, the word “sanctions” in
Article 7(F) naturally “includ[es]” monetary sanctions.
Since the Compact contains no definition of “sanctions,”
we give the word its ordinary meaning. A “sanction” (in
the sense the word is used here) is “[t]he detriment loss of
reward, or other coercive intervention, annexed to a viola­
tion of a law as a means of enforcing the law.” Webster’s
New International Dictionary 2211 (2d ed. 1957) (herein­
after Webster’s Second); see Black’s Law Dictionary 1458
(9th ed. 2009) (“A penalty or coercive measure that results
from failure to comply with a law, rule, or order”). A
monetary penalty is assuredly one kind of “sanction.” See
generally Department of Energy v. Ohio, 503 U. S. 607,
621 (1992). But there are many others, ranging from the
withholding of benefits, or the imposition of a nonmone­
tary obligation, to capital punishment. The Compact
surely does not authorize the Commission to impose all of
them.
   Ultimately, context dictates precisely which “sanctions”
are authorized under Article 7(F), and nothing in the
Compact suggests that these include monetary measures.
The only two “sanctions” specifically identified as being
included within Article 7(F) are “suspension” of a State’s
rights under the Compact and “revocation” of its status as
a party State. These are arguably merely examples, and
may not exhaust the universe of sanctions the Commission
                 Cite as: 560 U. S. ____ (2010)           9

                     Opinion of the Court

can impose. But they do establish “illustrative applica­
tion[s] of the general principle,” Federal Land Bank of St.
Paul v. Bismarck Lumber Co., 314 U. S. 95, 100 (1941),
which underlies the kinds of sanctions the Commission
can impose. It is significant that both these specifically
authorized sanctions are prospective and nonmonetary in
nature.
   Moreover, Article 3 of the Compact provides: “The rights
granted to the party [S]tates by this compact are addi­
tional to the rights enjoyed by sovereign states, and noth­
ing in this compact shall be construed to infringe upon,
limit, or abridge those rights.” 99 Stat. 1873. Construing
Article 7(F) to authorize monetary sanctions would violate
this provision, since the primeval sovereign right is im­
munity from levies against the government fisc. See, e.g.,
Alden v. Maine, 527 U. S. 706, 750–751 (1999).
   Finally, a comparison of the Compact’s terms with those
of “[o]ther interstate compacts, approved by Congress
contemporaneously,” Texas v. New Mexico, 462 U. S. 554,
565 (1983), confirms that Article 7(F) does not authorize
monetary sanctions. At the same time Congress consented
to this Compact, it consented to three other interstate
compacts that expressly authorize their commissions to
impose monetary sanctions against the parties to the
compacts. See Northeast Interstate Low-Level Radioac­
tive Waste Management Compact, Art. IV(i)(14), 99 Stat.
1915 (hereinafter Northeast Compact); Central Midwest
Interstate Low-Level Radioactive Waste Compact, Art.
VIII(f), 99 Stat. 1891 (hereinafter Central Midwest Com­
pact); Central Interstate Low-Level Radioactive Waste
Compact, Art. VII(e), 99 Stat. 1870 (hereinafter Central
Compact). The Compact “clearly lacks the features of
these other compacts, and we are not free to rewrite it” to
empower the Commission to impose monetary sanctions.
Texas v. New Mexico, 462 U. S., at 565.
10              ALABAMA v. NORTH CAROLINA 


                      Opinion of the Court 


                            B

  Because the Compact does not authorize the Commis­
sion to impose monetary sanctions, Plaintiffs’ second
exception—that North Carolina could not avoid monetary
sanctions by withdrawing from the Compact—is moot.
The third exception also pertains to the Commission’s
sanctions resolution: that North Carolina forfeited its
right to object to a monetary penalty by failing to partici­
pate at the sanctions hearing. Plaintiffs have failed to
argue this exception. They have merely noted that North
Carolina refused to participate at the sanctions hearing,
and have cited no law in support of the proposition that
this was a forfeit. We deem the exception abandoned. It
was wisely abandoned, because it is meritless. North
Carolina opposed the sanctions resolution and denied that
the Commission had jurisdiction to impose sanctions
against it.
                               C
  Plaintiffs next take exception to the Special Master’s
recommendation that no binding effect or even deference
be accorded to the Commission’s conclusion that North
Carolina violated Article 5(C) of the Compact. We are
bound by the Commission’s conclusion of breach only if
there is “an explicit provision or other clear indicatio[n]” in
the Compact making the Commission the “sole arbiter of
disputes” regarding a party State’s compliance with the
Compact. Id., at 569–570. Plaintiffs assert there is such a
provision, the second sentence of Article 7(C), which
states: “The Commission is the judge of the qualifications
of the party [S]tates and of its members and of their com­
pliance with the conditions and requirements of this com­
pact and the laws of the party [S]tates relating to the
enactment of this compact.” 99 Stat. 1879.
  Plaintiffs greatly overread this provision. The limited
nature of the authority to “judge” that it confers upon the
                  Cite as: 560 U. S. ____ (2010)           11

                      Opinion of the Court

Commission is clear from its context. The first sentence of
Article 7(C) states that an eligible State “shall be de­
clared” a party State “upon enactment of this compact into
law by the [S]tate and upon [the] payment of” a $25,000
fee, as “required by Article 4(H)(1).” Ibid. The second
sentence makes the Commission the “judge” of four mat­
ters, all of which concern status as a party State or Com
mission member. First, the Commission is the judge of the
“qualifications” of a State to become a party State (the
qualifications set forth in Article 7(A) for the initial party
States and in Article 7(B) for States that subsequently
petition to join). Second, the Commission is the judge of
the qualifications of the members of the Commission,
which are specified in Article 4(A). Third, the Commission
is the judge of a party State’s compliance with the “condi­
tions” and “requirements” of the Compact. The former
term is an obvious reference to Article 7(B): “The Commis­
sion may establish such conditions as it deems necessary
and appropriate to be met by a [S]tate wishing . . . to
become a party [S]tate to this [C]ompact.” Id., at 1878.
The accompanying term “requirements” also refers to
Article 7’s prescriptions for prospective party States, such
as paying the “fees required” under Article 7(C), id., at
1879, and obtaining, as Article 7(B) requires, a two-thirds
vote of the Commission in favor of admission. Finally, the
Commission is the judge of the “laws of the party [S]tates
relating to the enactment of this compact.” Art. 7(C), ibid.
Again, that concerns status as a party State, which re­
quires that the State “enac[t] . . . this compact into law,”
ibid. The Commission is the “judge” of only these specific
matters.
   This is not to say the Commission lacks authority to
interpret the Compact or to say whether a party State has
violated its terms. That is of course implicit in its power
to sanction under Article 7(F). But because “the express
terms of the [Southeast] Compact do not constitute the
12             ALABAMA v. NORTH CAROLINA

                      Opinion of the Court

Commission as the sole arbiter” regarding North Caro­
lina’s compliance with its obligations under the Compact,
Texas v. New Mexico, 462 U. S., at 569, we are not bound
to follow the Commission’s findings.
   Plaintiffs argue that we nonetheless owe deference to
the Commission’s conclusion. But unless the text of an
interstate compact directs otherwise, we do not review the
actions of a compact commission “on the deferential model
of judicial review of administrative action by a federal
agency.” Id., at 566–567. The terms of this Compact do
not establish that “this suit may be maintained only as
one for judicial review of the Commission’s” determination
of breach. Id., at 567. Accordingly, we do not apply ad­
ministrative-law standards of review, but exercise our
independent judgment as to both fact and law in executing
our role as the “exclusive” arbiter of controversies between
the States, §1251(a).
                              D
  Plaintiffs’ next two exceptions are to the Special Mas­
ter’s recommendations to deny their motion for summary
judgment on their breach-of-contract claims, and to grant
North Carolina’s motion for summary judgment on those
claims. In resolving motions for summary judgment in
cases within our original jurisdiction, we are not techni­
cally bound by the Federal Rules of Civil Procedure, but
we use Rule 56 as a guide. This Court’s Rule 17.2; Ne
braska v. Wyoming, 507 U. S. 584, 590 (1993). Hence,
summary judgment is appropriate where there “is no
genuine issue as to any material fact” and the moving
party is “entitled to a judgment as a matter of law.” Fed.
Rule Civ. Proc. 56(c); see Celotex Corp. v. Catrett, 477 U. S.
317, 322 (1986); Anderson v. Liberty Lobby, Inc., 477 U. S.
242, 248 (1986).
                  Cite as: 560 U. S. ____ (2010) 
         13

                      Opinion of the Court 


                               1

   Plaintiffs claim North Carolina breached the Compact in
December 1997, when (as it admits) it ceased all efforts
toward obtaining a license. At that point, in their view,
North Carolina was no longer “tak[ing] appropriate steps
to ensure that an application for a license to construct and
operate a [low-level radioactive waste storage facility] is
filed with and issued by the appropriate authority,” Art.
5(C), 99 Stat. 1877. North Carolina says that once the
Commission ceased providing financial assistance on
December 1, and once it became clear there was insuffi­
cient funding to complete the licensing phase, there were
no more “appropriate” steps to take. The Special Master
concluded that the phrase “appropriate steps” in Article
5(C) was ambiguous, and that the parties’ course of per­
formance established that North Carolina was not re­
quired to take steps toward obtaining a license once it was
made to bear the remaining financial burden of the licens­
ing phase. Second Report 10–24, 35–36. Plaintiffs take
exception to that conclusion.
   Article 5(C) does not require North Carolina to take any
and all steps to license a regional-disposal facility; only
those that are “appropriate.” Plaintiffs contend that this
requires North Carolina to take the steps set forth in the
regulations of the Nuclear Regulatory Commission govern­
ing the filing and disposition of applications for licenses to
operate radioactive waste disposal facilities, 10 CFR pt. 61
(1997). Those regulations set forth some, but certainly not
all, of the “steps” the State would have to take to obtain a
license. But Article 5(C) does not incorporate the regula­
tions by reference, much less describe them as the appro
priate steps.
   We could accept Plaintiffs’ contention if “appropriate”
meant “necessary” (the steps set forth in the regulation
are assuredly necessary to obtaining a license). But it
does not. Whether a particular step is “appropriate”—
14             ALABAMA v. NORTH CAROLINA

                     Opinion of the Court

“[s]pecially suitable; fit; proper,” Webster’s Second 133—
could depend upon many factors other than its mere in­
dispensability to obtaining a license. It would not be
appropriate, for example, to take a step whose cost greatly
exceeded whatever benefits the license would confer, or if
it was highly uncertain the license would ever issue.
   In determining whether, in terminating its efforts to
obtain a license, North Carolina failed to take what the
parties considered “appropriate” steps, the parties’ course
of performance under the Compact is highly significant.
See, e.g., New Jersey v. New York, 523 U. S. 767, 830–831
(1998) (SCALIA, J., dissenting); Restatement (Second) of
Contracts §§202(4), 203 (1979) (hereinafter Restatement).
That firmly establishes that North Carolina was not ex­
pected to go it alone—to proceed with the very expensive
licensing process without any external financial assis­
tance. The history of the Compact consists entirely of
shared financial burdens. From the beginning, North
Carolina made clear that it required financial assistance
to do the extensive work required for obtaining a license.
The Commission promptly declared it was “appropriate
and necessary” to assist North Carolina with the costs.
App. 63. It provided the vast majority of funding for li­
censing-related activities—$80 million, compared to North
Carolina’s $34 million. The Commission repeatedly noted
the necessity (and propriety) of providing financial assis­
tance to North Carolina, and reiterated its dedication to
sharing the substantial financial burdens of the licensing
phase. See, e.g., id., at 63, 71, 145. There is nothing to
support the proposition that the other States had an obli­
gation under the Compact to share the licensing costs
through the Commission; but we doubt that they did so
out of love for the Tarheel State. They did it, we think,
because that was their understanding of how the Compact
was supposed to work. One must take the Commission at
its word, that it was “appropriate” to share the cost—
                 Cite as: 560 U. S. ____ (2010)           15

                     Opinion of the Court

which suggests that it would not have been appropriate to
make North Carolina proceed on its own.
   Nor was North Carolina required after December 19,
1997, to continue to expend its own funds at the same
level it had previously (which Plaintiffs concede had satis­
fied North Carolina’s obligation to take “appropriate
steps”). Once the Commission refused to provide any
further financial assistance, North Carolina would have
had to assume an unlimited financial commitment to cover
all remaining licensing costs. Even if it maintained its
prior rate of appropriations going forward, it would not
have come close to covering the at least $34 million needed
for the last steps of the licensing phase. And since the
income from the South Carolina facility had been termi­
nated, there was no apparent prospect of funding for the
construction phase (expected to cost at least $75 million).
In connection with its August 1997 refusal to provide
further assistance, the Commission itself had said, “[I]t
will be imprudent to continue to deplete Commission
resources for this purpose if a source of funds is not estab­
lished soon for the ultimate completion of the project.” Id.,
at 306, 307; Joint Supp. Fact Brief App. 36, 37. And in
March 1998, the Commission “strongly” reiterated that “it
would be imprudent to spend additional funds for licens­
ing activities if funds will not be available to complete the
project.” Id., at 59. What was imprudent for the Commis­
sion would surely have been imprudent (and hence inap­
propriate) for North Carolina as well. The State would
have wasted millions of its taxpayers’ dollars on what
seemed to be a futile effort.
   JUSTICE BREYER would uphold Plaintiffs’ challenge on
this point. He believes that the Compact obligated North
Carolina to fund and complete the licensing and construc­
tion of a nuclear waste facility. Post, at 2, 4–6 (opinion
concurring in part and dissenting in part). In fact, how­
ever, North Carolina was not even contractually required
16                 ALABAMA v. NORTH CAROLINA

                          Opinion of the Court

to “secur[e] a license,” post, at 2, but only to take “appro­
priate steps” to obtain one, Art. 5(C), 99 Stat. 1877. And
nothing in the terms of the Compact required North Caro­
lina either to provide “adequate funding” for or to “beg[i]n
construction” on a regional facility, post, at 2. Other con­
temporaneously enacted interstate compacts expressly
provide that the host State is “responsible for the timely
development” of a regional facility, Central Midwest Com­
pact, Art. VI(f), 99 Stat. 1887; Midwest Compact,
Art. VI(e), id., at 1898, or “shall . . . [c]ause a regional
facility to be developed on a timely basis,” Rocky Mountain
Low-Level Radioactive Waste Compact, Art. III(d)(i), id.,
at 1903–1904. But the compact here before us has no such
provision, and the contrast is telling.1 Texas v. New Mex
ico, 462 U. S., at 565. Moreover, the Commission’s state­
ments described in the preceding paragraph, that it would
be imprudent to commit additional resources “ ‘if a source
of funds is not established soon for the ultimate comple­
tion of the project,’ ” or “ ‘if funds will not be available to
complete the project,’ ” surely suggest that North Carolina
is not committed to the funding by contract.
   JUSTICE BREYER asserts, post, at 4–5, that the rotating­

——————
   1 The Compact provides only that the host State is “responsible for

the availability . . . of their regional facilities in accordance with”
Article 5(B). Art. 3(C), 99 Stat. 1873–1874. The latter section makes
clear that responsibility for “availability” does not mean that the host
State will fund construction of the facility, but that it will keep it open
and not impose unreasonable restrictions on its use. JUSTICE BREYER is
correct that the Compact says the Commission is not “responsible” for
the costs of “the creation” of a regional facility. Art. 4(K)(1), id., at
1876. But what is important here is that it does not say that the host
State is responsible—which (if it were true) would almost certainly
have been joined with saying who was not responsible. What JUSTICE
BREYER overlooks is the possibility that no one is responsible, and the
licensing and construction of the facility is meant to depend upon
voluntary funding by interested parties, such as the party States, the
Commission, and low-level radioactive waste generators.
                     Cite as: 560 U. S. ____ (2010)                   17

                          Opinion of the Court

host requirement in the Compact, see Art. 5(A), 99 Stat.
1873, necessarily implies that North Carolina is solely
responsible for the licensing and construction costs of its
facility. But all that requirement entails is that a party
State “shall not be designated” as a host State for a second
time before “each [other] party [S]tate” has taken a turn.
Ibid. It can perfectly well envision that the States will
take turns in bearing the lead responsibility for getting
the facility licensed, supervising its construction, and
operating the facility on its soil. In fact, that is just what
its text suggests, since it describes the responsibility that
is to be rotated as the host State’s “obligation . . . to have a
regional facility operated within its borders.” Ibid. Not to
construct it, or pay for its construction, but to “have [it]
operated within its borders.” As noted above, other con­
temporaneously enacted compacts do spell out the obliga­
tion of the host State to construct the facility. Still others
at least provide that the host State will recoup its costs
through disposal fees—which arguably suggests that the
host State is to bear the costs. See, e.g., Central Compact,
Art. III(d),    99    Stat.  1865;     Northeast       Compact,
Art. III(c)(2), id., at 1913. The compact before us here
does not even contain that arguable suggestion.
   What it comes down to, then, is JUSTICE BREYER’s intui­
tion that the whole point of the Compact was that each
designated host State would bear the up-front costs of
licensing and construction, but would eventually recoup
those costs through its regional monopoly on the disposal
of low-level radioactive waste. Post, at 5–6. He can cite no
provision in the Compact which reflects such an under­
standing, and the behavior of the parties contradicts it.2 It
——————
  2 The course-of-dealing evidence that JUSTICE BREYER identifies, post,

at 6–7, is not probative. The Commission’s statements that it is not
legally responsible for costs and that at some point Commission funds
will no longer be available, and North Carolina’s assurances that it will
keep its commitments and honor its obligations, are perfectly compati­
18                 ALABAMA v. NORTH CAROLINA

                          Opinion of the Court

would, moreover, have been a foolish understanding, since
the regional monopoly to recoup construction costs would
not be a monopoly if South Carolina withdrew and contin­
ued to operate its facility—which is exactly what hap­
pened in 1995.3 Even leaving aside the principle, dis­
cussed infra, at 21, that implied obligations are not to be
read into interstate compacts, JUSTICE BREYER’s intuition
fails to reflect the reality of what was implied.
                              2
   Plaintiffs take exception to the Special Master’s rejec­
tion of their alternative argument that North Carolina
repudiated the Compact when it announced it would not
take further steps toward obtaining a license. They argue
that North Carolina’s announcement that it was shutting
down the project constituted a refusal to tender any fur­
ther performance under the contract.
   Plaintiffs’ repudiation theory fails for the same reasons
their breach theory fails. A repudiation occurs when an
obligor either informs an obligee “that the obligor will
——————
ble with the proposition that North Carolina did not have to provide all
funding for licensing the facility, and that it would be “inappropriate” to
proceed toward obtaining a license for a facility that would never be
needed or built.
  3 South Carolina’s withdrawal from the Compact not only “could”

affect North Carolina’s ability to recoup its facility costs, as JUSTICE
BREYER grudgingly concedes, post, at 5; it unquestionably would. With
a regional competitor in the Barnwell facility and declining demand for
waste disposal facilities due to technological and other factors, App.
261, 263–264, North Carolina would receive significantly lower reve­
nues from its facility, id., at 261–262, 265. The document attached to a
1996 letter from North Carolina to the Commission trumpeting “$600
million in cost savings” that would come from a new facility, post, at 5,
proves precisely the opposite of what JUSTICE BREYER thinks. The cost
savings were to accrue “to all generators” of waste, App. 266 (emphasis
added)—that is, those who would use North Carolina’s facility. Those
savings would come, of course, from lower costs for waste disposal,
which means that North Carolina would be charging lower rates than
the Barnwell facility (and thus receiving lower revenues).
                  Cite as: 560 U. S. ____ (2010)            19

                      Opinion of the Court

commit a breach that would of itself give the obligee a
claim for damages for total breach,” Restatement §250(a),
or performs “a voluntary affirmative act which renders the
obligor unable or apparently unable to perform without
such a breach,” id., §250(b). Neither event occurred here.
North Carolina never informed the Commission (or any
party State) that it would not fulfill its Article 5(C) obliga­
tion to take appropriate steps toward obtaining a license.
Rather, it refused to take further steps that were not
appropriate. Nor did North Carolina take an affirmative
act that rendered it unable to perform. To the contrary, it
continued to fund the Authority for almost two years; it
maintained the records of the Authority; and it preserved
the work completed to date while waiting for alternative
funding sources that would enable resumption of the
project. Plaintiffs further argue that a repudiation was
effected by North Carolina’s refusal to take further steps
toward licensing “except on conditions which go beyond”
the terms of the Compact, Restatement §250, Comment b
(internal quotation marks omitted)—i.e., the provision of
external-financial assistance. But, as we have discussed,
external-financial assistance was contemplated by the
Compact.
                              E
   Plaintiffs’ final exception is to the Special Master’s
recommendation to deny their motion for summary judg­
ment, and to grant North Carolina’s cross-motion for
summary judgment, on their claim that North Carolina
violated the implied duty of good faith and fair dealing
when it withdrew from the Compact in July 1999. Plain­
tiffs concede that North Carolina could withdraw from the
Compact, but contend it could not do so in “bad faith.”
And, they assert, its withdrawal after accepting $80 mil­
lion from the Commission, and with monetary sanctions
pending against it, was the epitome of bad faith.
20                ALABAMA v. NORTH CAROLINA

                         Opinion of the Court

   We have never held that an interstate compact approved
by Congress includes an implied duty of good faith and
fair dealing. Of course “[e]very contract imposes upon
each party a duty of good faith and fair dealing in its
performance and enforcement.” Restatement §205. But
an interstate compact is not just a contract; it is a federal
statute enacted by Congress. If courts were authorized to
add a fairness requirement to the implementation of
federal statutes, judges would be potent lawmakers in­
deed. We do not—we cannot—add provisions to a federal
statute. See, e.g., Connecticut Nat. Bank v. Germain, 503
U. S. 249, 254 (1992). And in that regard a statute which
is a valid interstate compact is no different. Texas v. New
Mexico, 462 U. S., at 564, 565. We are especially reluctant
to read absent terms into an interstate compact given the
federalism and separation-of-powers concerns that would
arise were we to rewrite an agreement among sovereign
States, to which the political branches consented. As we
have said before, we will not “ ‘order relief inconsistent
with [the] express terms’ ” of a compact, “no matter what
the equities of the circumstances might otherwise invite.”
New Jersey v. New York, 523 U. S., at 811 (quoting Texas
v. New Mexico, supra, at 564).
   The Compact imposes no limitation on North Carolina’s
exercise of its statutory right to withdraw. Under Article
7(G), which governed North Carolina’s withdrawal,4 “any
party [S]tate may withdraw from the compact by enacting
a law repealing the compact.” 99 Stat. 1879. There is no
restriction upon a party State’s enactment of such a law,
——————
  4 After North Carolina was designated as a host State, the Compact

was amended to add Article 7(H), which restricted the ability of a party
State to withdraw to within 30 days after a second regional-disposal
facility opened. Southeast Interstate Low-Level Radioactive Waste
Compact Amendments Consent Act of 1989, Pub. L. 101–171, §2, 103
Stat. 1289. That provision did not apply when North Carolina with­
drew, because its facility had not been opened.
                 Cite as: 560 U. S. ____ (2010)          21

                     Opinion of the Court

and nothing in the Compact suggests the parties under­
stood there were “certain purposes for which the expressly
conferred power . . . could not be employed.” Tymshare,
Inc. v. Covell, 727 F. 2d 1145, 1153 (CADC 1984) (opinion
for the court by Scalia, J.). Moreover, Article 3 ensures
that no such restrictions may be implied, since it provides
that the Compact shall not be “construed to infringe upon,
limit or abridge” the sovereign rights of a party State.
   A comparison of the Compact with other, contemporane­
ously enacted, compacts confirms there is no such limita­
tion on North Carolina’s right to withdraw. See Texas v.
New Mexico, supra, at 565. In contrast to the Compact,
several other compacts concerning the creation of regional
facilities for the disposal of low-level radioactive waste
contain express good-faith limitations upon a State’s
exercise of its rights.      See, e.g., Central Compact,
Art. III(f), 99 Stat. 1865; Central Midwest Compact,
Art. V(a), id., at 1886; Midwest Interstate Low-Level
Radioactive Waste Management Compact, Art. V(a), id., at
1897.
                           III
  North Carolina submits two exceptions—one to the
Special Master’s Second Report and one to his Preliminary
Report.
                             A
   North Carolina takes exception to the recommendation
of the Second Report to deny without prejudice its motion
for summary judgment on the merits of Plaintiffs’ equita­
ble claims in Counts III–V. North Carolina’s motion was
based on the ground that, as a matter of law, its obliga­
tions are governed entirely by the Compact. The Special
Master recommended denying the motion without preju­
dice, because the claims in Counts III–V “requir[e] further
briefing and argument, and possibly further discovery.”
22                ALABAMA v. NORTH CAROLINA

                         Opinion of the Court

Second Report 41. A threshold question for all claims in
those Counts, for example, is whether they “belong to the
Commission, the Plaintiff States, or both.” Ibid. Perhaps
the States can bring them in their capacity as parens
patriae, but as the Special Master noted “the parties have
not adequately briefed this issue, and its resolution in this
case is unclear.” Id., at 42–43.
  We think it was reasonable for the Special Master to
defer ruling. We granted the Special Master discretion to
“direct subsequent proceedings” and “to submit such re­
ports as he may deem appropriate.” 540 U. S., at 1014.
He could have deferred filing any report until full factual
discovery had been completed and all of the legal issues,
many of which are novel and challenging, had been fully
briefed, considered, and decided. Instead, he concluded
that our immediate resolution of Counts I and II would
facilitate the efficient disposition of the case; and in agree­
ing to hear exceptions to his Preliminary Report and
Second Report we implicitly agreed. His deferral of ruling
on the merits of Counts III–V is part and parcel of the
same case management, and we find no reason to upset it.
                            B
   North Carolina takes exception to the Special Master’s
recommendation in his Preliminary Report to deny with­
out prejudice its motion to dismiss the Commission’s
claims on the ground that they are barred by the Eleventh
Amendment to the Constitution and by structural princi­
ples of state sovereign immunity. The Special Master
assumed for the sake of argument that a State possesses
sovereign immunity against a claim brought by an entity,
like the Commission, created by an interstate compact,5
——————
  5 We have held that an entity created through a valid exercise of the
Interstate Compact Clause is not entitled to immunity from suit under
the Eleventh Amendment, see Hess v. Port Authority Trans-Hudson
Corporation, 513 U. S. 30 (1994), but we have not decided whether such
                     Cite as: 560 U. S. ____ (2010)                   23

                          Opinion of the Court

Preliminary Report 5. But he recommended denying
North Carolina’s motion to dismiss “at this point in the
proceedings.” Ibid.
  The Special Master relied upon our decision in Arizona
v. California, 460 U. S. 605 (1983), which held that the
Eleventh Amendment did not bar the participation of
several Indian Tribes in an original action concerning the
allocation of rights to the waters of the Colorado River.
The United States had already intervened, in its capacity
as trustee for several Indian Tribes; but the Tribes moved
to intervene as well, and the States opposed. We granted
the Tribes’ motion, stating that the States do not enjoy
sovereign immunity against the United States, and “[t]he
Tribes do not seek to bring new claims or issues against
the States, but only ask leave to participate in an adjudi­
cation of their vital water rights that was commenced by
the United States.” Id., at 614. Thus, “our judicial power
over the controversy is not enlarged by granting leave to
intervene, and the States’ sovereign immunity protected
by the Eleventh Amendment is not compromised.” Ibid.
Relying on this holding, the Special Master held that
sovereign immunity does not bar the Commission’s suit, so
long as the Commission asserts the same claims and seeks
the same relief as the other plaintiffs. Whether that is so,
he said, “cannot be resolved without further factual and
legal development[s],” Preliminary Report 6, and so North
Carolina is free to renew its motion at a later point, id., at
13–14. See Second Report 45–48.
 Assuming (as the Special Master did) that the Commis­
sion’s claims against North Carolina implicate sovereign
immunity, we agree with his disposition. North Carolina
contends that making application of the Constitution’s
waiver of sovereign immunity turn upon whether a
nonsovereign party seeks to expand the relief sought is
—————— 

an entity’s suit against a State is barred by sovereign immunity. 

24                ALABAMA v. NORTH CAROLINA

                         Opinion of the Court

inconsistent with our decisions construing state sovereign
immunity as a “personal privilege.” College Savings Bank
v. Florida Prepaid Postsecondary Ed. Expense Bd., 527
U. S. 666, 675 (1999) (internal quotation marks omitted);
see also Alden, 527 U. S., at 758. But nothing in those
cases suggests that Arizona v. California has been implic­
itly overruled.6 See Shalala v. Illinois Council on Long
Term Care, Inc., 529 U. S. 1, 18 (2000). Neither of them
arose under our original jurisdiction, and neither cited
Arizona v. California or discussed—at all—the sovereign
immunity issue that case addressed. That sovereign
immunity is a personal privilege of the States says noth­
ing about whether that privilege “is not compromised,”
Arizona v. California, supra, at 614, by an additional,
nonsovereign plaintiff’s bringing an entirely overlapping
claim for relief that burdens the State with no additional
defense or liability.7
   North Carolina contends that Arizona v. California
cannot apply to the Commission’s claims, because the
Commission does not—indeed, cannot—assert the same
claims or seek the same relief as the plaintiff States. We
disagree. In the bill of complaint, the States and the
Commission assert the same claims and request the same
relief. Bill of Complaint ¶¶62–86 and Prayer for Relief.
Their claim for restitution of $80 million cannot, given the

——————
  6 North Carolina has not asked us to overrule Arizona v. California,
460 U. S. 605 (1983). We decline to do so on our own motion and
without argument. We therefore do not address the merits of THE
CHIEF JUSTICE’s dissent.
  7 North Carolina also asserts that our decisions in Pennhurst State

School and Hospital v. Halderman, 465 U. S. 89 (1984), and County of
Oneida v. Oneida Indian Nation of N. Y., 470 U. S. 226 (1985), under­
mine Arizona v. California, supra, at 614. They do not. In neither case
were there entirely overlapping claims for relief between sovereign and
nonsovereign plaintiffs. See Pennhurst, supra, at 103, n. 12. Indeed, in
County of Oneida there was no sovereign plaintiff.
                  Cite as: 560 U. S. ____ (2010)           25

                      Opinion of the Court

other allegations of the complaint, be thought to be $80
million payable to each of the four plaintiff States and the
Commission.
   North Carolina argues, however, that summary judg­
ment in its favor is appropriate because it is clear that the
Commission, and not the plaintiff States, provided $80
million to North Carolina—wherefore, as a matter of law,
only the Commission can claim entitlement to $80 million,
either as a measure of damages for breach of the Compact
under Counts I and II of the bill of complaint, see Re­
statement §370, Comment a, and §373, or under the un­
just enrichment, promissory estoppel, and money-had-and­
received theories of recovery in Counts III, IV, and V, see,
e.g., Restatement of Restitution §1, Comment a (1936).
And, it contends, a stand-alone suit by the Commission is
barred by sovereign immunity.
   With regard to Counts I and II, at least, we disagree.
The Commission’s claims under those Compact-related
Counts are wholly derivative of the States’ claims. See
Arizona v. California, supra, at 614. The Commission is
“a legal entity separate and distinct from” the States that
are parties to the Compact. Art. 4(M)(1), 99 Stat. 1877.
Since it is not a party it has neither a contractual right to
performance by the party States nor enforceable statutory
rights under Article 5 of the Compact, see Bennett v.
Spear, 520 U. S. 154, 162–163 (1997). The Compact does,
however, authorize the Commission to “act or appear on
behalf of any party [S]tate or [S]tates . . . as an intervenor
or party in interest before . . . any court of law,” Art.
4(E)(10), 99 Stat. 1875, and it is obviously in this capacity
that the Commission seeks to vindicate the plaintiff
States’ statutory and contractual rights in Counts I and II.
Its Count I and Count II claims therefore rise or fall with
the claims of the States. While the Commission may not
bring them in a stand-alone action under this Court’s
original jurisdiction, see §1251(a), it may assert them in
26             ALABAMA v. NORTH CAROLINA

                     Opinion of the Court

this Court alongside the plaintiff States, see Arizona v.
California, 460 U. S., at 614. The summary judgment
disallowing the underlying claims on their merits renders
the sovereign immunity question with regard to any relief
the Commission alone might have on those claims moot.
  Counts III–V, which do not rely upon the Compact,
stand on a different footing. As to them, while the Com­
mission again seemingly makes the same claims and seeks
the same relief as the States, it is conceivable that as a
matter of law the Commission’s claims are not identical.
The Commission can claim restitution as the party that
paid the money to North Carolina; the other plaintiffs
cannot claim it on that basis. Whether this means that
the claims are not identical for Arizona v. California pur­
poses, and that the Commission’s Counts III–V claims
must be dismissed on sovereign immunity grounds, is a
question that the Special Master declined to resolve until
the merits issues were further clarified. We have ap­
proved his deferral of those issues, and we likewise ap­
prove his deferral of the related sovereign immunity issue.
                        *    *    *
  We overrule the exceptions of Plaintiffs and North
Carolina to the Special Master’s Reports, and we adopt the
recommendations of the Special Master. We grant North
Carolina’s motion to dismiss Count I. We grant North
Carolina’s motion for summary judgment on Count II. We
deny Plaintiffs’ motions for judgment on Counts I and II.
And we deny without prejudice North Carolina’s motion to
dismiss the Commission’s claims on the grounds of sover­
eign immunity and its motion for summary judgment on
Counts III–V.
                                            It is so ordered.
                 Cite as: 560 U. S. ____ (2010)           1

                    Opinion of KENNEDY, J.

SUPREME COURT OF THE UNITED STATES
                         _________________

                        No. 132, Orig.
                         _________________


STATE OF ALABAMA, STATE OF FLORIDA, STATE OF

 TENNESSEE, COMMONWEALTH OF VIRGINIA, AND

  SOUTHEAST INTERSTATE LOW-LEVEL RADIO- 

   ACTIVE WASTE MANAGEMENT COMMISSION, 

    PLAINTIFFS v. STATE OF NORTH CAROLINA

ON EXCEPTIONS TO THE PRELIMINARY AND SECOND REPORTS
               OF THE SPECIAL MASTER
                        [June 1, 2010]

   JUSTICE KENNEDY, with whom JUSTICE SOTOMAYOR
joins, concurring in part and concurring in the judgment.
   The Court is correct, in my view, to conclude that we
may not “add provisions to a federal statute.” Ante, at 20.
Plaintiffs do not request as much, however, in contending
that North Carolina was required by the Compact to carry
out its obligations in good faith. Rather, plaintiffs’ argu
ment is that the Compact’s terms, properly construed,
speak not only to the specific duties imposed upon the
parties but also to the manner in which those duties must
be carried out. This is an interpretive argument familiar
to contract disputes. See, e.g., Restatement (Second) of
Contracts §205 (1979) (hereinafter Restatement).
   As the opinion for the Court notes, congressional con
sent to an interstate compact gives it the status of a fed
eral statute. See ante, at 20. This is an apt and proper
way to indicate that a compact has all the dignity of an
Act of Congress. And that is surely what was meant in
New Jersey v. New York, 523 U. S. 767, 811 (1998), where
it was stated that the Court may not “ ‘order relief incon
sistent with [the] express terms’ ” of a compact. Ante, at
20 (quoting New Jersey; alteration in original; some inter
2              ALABAMA v. NORTH CAROLINA

                    Opinion of KENNEDY, J.

nal quotation marks omitted); see also Cuyler v. Adams,
449 U. S. 433, 438 (1981) (“[C]ongressional consent trans
forms an interstate compact . . . into a law of the United
States”).
  From this principle, however, it simply does not follow
that a law’s nature and origin as a compact must be dis
missed as irrelevant. Like a treaty, a compact represents
an agreement between parties. See New Jersey, supra, at
831 (SCALIA, J., dissenting) (“[T]he Compact here is of
course a treaty”). The Court’s duty in interpreting a com
pact involves ascertaining the intent of the parties. See
Sullivan v. Kidd, 254 U. S. 433, 439 (1921) (“[T]reaties are
to be interpreted upon the principles which govern the
interpretation of contracts . . . with a view to making
effective the purposes of the high contracting parties”);
Wright v. Henkel, 190 U. S. 40, 57 (1903) (“Treaties must
receive a fair interpretation, according to the intention of
the contracting parties”). Carrying out this duty may lead
the Court to consult sources that might differ from those
normally reviewed when an ordinary federal statute is at
issue. That much is surely implicit in the Court’s refer
ence to contract law principles elsewhere in its opinion in
the instant case. See, e.g., ante, at 14 (“[T]he parties’
course of performance under the Compact is highly signifi
cant”); ibid. (citing the Restatement); id., at 18–19 (same);
see also New Jersey, supra, at 830–831 (SCALIA, J., dis
senting) (construing a compact in light of “hornbook con
tracts law that the practical construction of an ambiguous
agreement revealed by later conduct of the parties is good
indication of its meaning”).
  That said, it is quite correct to hold here that the rea
sonable expectations of the contracting States, as mani
fested in the Compact, do not reveal an intent to limit
North Carolina’s power of withdrawal. For purposes of
rejecting this argument, it is sufficient to note—as the
Court does—that the Compact permits any State to with
                  Cite as: 560 U. S. ____ (2010)            3

                     Opinion of KENNEDY, J.

draw; imposes no limitation on this right; and explicitly
provides that the Compact shall not be construed to
abridge the sovereign rights of any party State. See ante,
at 20–21. Federalism concerns also counsel reluctance to
find that a State has implicitly restricted its sovereignty in
such a manner.
   The Court is therefore correct to reject plaintiffs’ final
exception. With these observations, I join the Court’s
opinion with the exception of Part II–E.
                 Cite as: 560 U. S. ____ (2010)            1

                   Opinion of ROBERTS, C. J.

SUPREME COURT OF THE UNITED STATES
                         _________________

                        No. 132, Orig.
                         _________________


STATE OF ALABAMA, STATE OF FLORIDA, STATE OF

 TENNESSEE, COMMONWEALTH OF VIRGINIA, AND

  SOUTHEAST INTERSTATE LOW-LEVEL RADIO- 

   ACTIVE WASTE MANAGEMENT COMMISSION, 

    PLAINTIFFS v. STATE OF NORTH CAROLINA

ON EXCEPTIONS TO THE PRELIMINARY AND SECOND REPORTS
               OF THE SPECIAL MASTER
                        [June 1, 2010]

   CHIEF JUSTICE ROBERTS, with whom JUSTICE THOMAS
joins, concurring in part and dissenting in part.
   The parties to this case are Alabama, Florida, North
Carolina, Tennessee, Virginia, and the Southeast Inter
state Low-Level Radioactive Waste Management Commis
sion. One of these things is not like the others: The Com
mission is not a sovereign State. The Court entertains its
suit—despite North Carolina’s sovereign immunity—
because the Commission “asserts the same claims and
seeks the same relief as the other plaintiffs.” Ante, at 23.
Our Constitution does not countenance such “no harm, no
foul” jurisdiction, and I respectfully dissent.
   The Court has made this mistake before. In Arizona v.
California, 460 U. S. 605 (1983), we allowed Indian Tribes
that could not sue sovereign States to piggyback on the
claims of the United States, which could. We reasoned
that once the United States had initiated suit, the state
defendants could “no longer . . . assert [their] immunity
with respect to the subject matter of [the] action,” so the
Tribes were free to pile on and join the suit. Id., at 614.
Today the Court retraces Arizona’s steps, quoting that
case for the proposition that when private plaintiffs “ ‘do
2              ALABAMA v. NORTH CAROLINA

                   Opinion of ROBERTS, C. J.

not seek to bring new claims or issues, . . . our judicial
power over the controversy is not enlarged . . . , and the
States’ sovereign immunity protected by the Eleventh
Amendment is not compromised.’ ” Ante, at 23 (quoting
Arizona, supra, at 614).
  That statement is contrary to the language of the Con
stitution. The Eleventh Amendment provides:
      “The Judicial power of the United States shall not
    be construed to extend to any suit in law or equity,
    commenced or prosecuted against one of the United
    States by Citizens of another State, or by Citizens or
    Subjects of any Foreign State.”
The immunity conferred is against the “commence[ment]
or prosecut[ion]” of “any suit in law or equity.” There is no
carve-out for suits “prosecuted” by private parties so long
as those parties “ ‘do not seek to bring new claims or is
sues.’ ” Ante, at 23 (quoting Arizona, supra, at 614).
   Understandably, the Court’s opinion leans heavily on
Arizona, which has never been squarely overruled. Ante,
at 23–24. But Arizona itself is built on sand. The relevant
portion of that opinion is almost wholly unreasoned. It
cites only a footnote in a prior case, the pertinent para
graph of which failed even to discuss the State’s immunity
from private suit. See 460 U. S., at 614 (citing Maryland
v. Louisiana, 451 U. S. 725, 745, n. 21 (1981)). That para
graph addressed only intervention, not sovereign immu
nity, and the two issues are distinct. See South Carolina
v. North Carolina, 558 U. S. ___, ___, n. 5 (2010) (slip op.,
at 10, n. 5).
   Most importantly, the subsequent development of our
sovereign immunity jurisprudence has only undermined
Arizona’s already weak foundations. We recognized in
Alden v. Maine, 527 U. S. 706, 718 (1999), that the Consti
tution left intact the States’ pre-existing “immunity from
private suits”; as the Eleventh Amendment confirms, the
                  Cite as: 560 U. S. ____ (2010)            3

                    Opinion of ROBERTS, C. J.

States did not “ ‘surrender . . . this immunity in the plan of
the convention.’ ” Id., at 717 (quoting The Federalist No.
81, p. 487 (C. Rossiter ed. 1961) (A. Hamilton)); see also
Alden, supra, at 718–722, 755–756. There is no reason to
suppose that the States, at the founding, made an excep
tion for private suits that happen to mimic other plaintiffs’
claims—and neither Arizona nor the Court today suggests
otherwise.
   Whether or not a plaintiff “seeks the same relief” or
imposes any “additional defense or liability,” ante, at 23–
24, simply does not matter in light of our recognition that
sovereign immunity provides an “immunity from suit,” not
a “defense to . . . liability.” Federal Maritime Comm’n v.
South Carolina Ports Authority, 535 U. S. 743, 766 (2002).
As we have explained, “the relief sought by a plaintiff
suing a State is irrelevant to the question whether the suit
is barred.” Seminole Tribe of Fla. v. Florida, 517 U. S. 44,
58 (1996). Indeed, we have suggested that private parties
may not sue even if a court is “precluded . . . from award
ing them any relief.” Federal Maritime Comm’n, supra, at
766 (emphasis added) (dictum). It is the fact that a pri
vate party is allowed to sue a sovereign State—not the
burden of litigation or the relief sought—that infringes the
immunity of the State. “The Eleventh Amendment is
concerned not only with the States’ ability to withstand
suit, but with their privilege not to be sued.” Puerto Rico
Aqueduct and Sewer Authority v. Metcalf & Eddy, Inc.,
506 U. S. 139, 147, n. 5 (1993).
   It is therefore impossible for the Court to hear private
claims against a nonconsenting State without expanding
“our judicial power over the controversy.” Arizona, supra,
at 614. Sovereign immunity is a limitation on that power.
The similarity of claims may be relevant to joinder or
intervention, but those are procedural means of processing
claims, not fonts of judicial authority. See Henderson v.
United States, 517 U. S. 654, 664 (1996).
4                 ALABAMA v. NORTH CAROLINA

                       Opinion of ROBERTS, C. J.

   Nor may the Court entertain private claims without
“compromis[ing]” “the States’ sovereign immunity.” Ari
zona, 460 U. S., at 614. As a party, the Commission enjoys
legally enforceable rights against the defendant State: It
may object to settlement, seek taxation of costs, advance
arguments we are obliged to consider, and plead the
judgment as res judicata in future litigation. If the Com
mission truly sought nothing for itself—other than “a full
exposition of the issues,” Preliminary Report of the Special
Master 14—it could have participated as an amicus.
   The Commission and North Carolina know that more is
at stake if the Commission is allowed to sue the State. It
is precisely the Commission’s status as a party, its attempt
to “prosecut[e]” a “suit in law or equity . . . against one of
the United States,” U. S. Const., Amdt. 11, that sovereign
immunity forbids.
   I would sustain North Carolina’s first exception to the
Special Master’s reports.*




——————
  * I also join JUSTICE BREYER’s opinion and all of the Court’s opinion
save Parts II–D and III–B. JUSTICE THOMAS joins all but Part III–B of
the Court’s opinion.
                  Cite as: 560 U. S. ____ (2010)            1

                      Opinion of BREYER, J.

SUPREME COURT OF THE UNITED STATES
                          _________________

                         No. 132, Orig.
                          _________________


STATE OF ALABAMA, STATE OF FLORIDA, STATE OF

 TENNESSEE, COMMONWEALTH OF VIRGINIA, AND

  SOUTHEAST INTERSTATE LOW-LEVEL RADIO- 

   ACTIVE WASTE MANAGEMENT COMMISSION, 

    PLAINTIFFS v. STATE OF NORTH CAROLINA

ON EXCEPTIONS TO THE PRELIMINARY AND SECOND REPORTS
               OF THE SPECIAL MASTER
                         [June 1, 2010]

  JUSTICE BREYER, with whom THE CHIEF JUSTICE joins,
concurring in part and dissenting in part.
  I join Parts I, II–A, II–B, and III of the Court’s opinion.
Unlike the Court, however, I believe that North Carolina
breached the Southeast Interstate Low-Level Radioactive
Waste Management Compact (Compact) when it sus­
pended its efforts toward building a waste disposal facility.
(THE CHIEF JUSTICE joins all but Parts II–D and III–B of
the Court’s opinion.)
  Article 5(C) is the critical term of the Compact. It states:
    “Each party state designated as a host state for a re­
    gional facility shall take appropriate steps to ensure
    that an application for a license to construct and op­
    erate a facility . . . is filed with and issued by the ap­
    propriate authority.” Omnibus Low-Level Radioactive
    Waste Interstate Compact Consent Act (Consent Act),
    99 Stat. 1877.
In September 1986, North Carolina was “designated as a
host state for a regional” low-level nuclear waste disposal
“facility.” Ibid.; see also App. 417, 432. Soon thereafter,
North Carolina’s General Assembly enacted legislation
2               ALABAMA v. NORTH CAROLINA

                      Opinion of BREYER, J.

authorizing a state agency to “site, finance, [and] build” a
waste disposal facility. N. C. Gen. Stat. §104G–4 (1987)
(repealed 2000). Pursuant to this legislation, a new facil­
ity was to be completed by January 1, 1993. Ibid.
   From August 1987 until December 1997, North Carolina
took a series of steps to prepare for the construction of the
storage facility. See Brief for North Carolina in Support of
Exceptions to Reports of the Special Master 6–8. And
while doing so it continually assured its Compact partners
that it “remain[ed] committed to fulfilling its obligations to
the Compact to serve as the next host state.” App. 92
(Letter from James G. Martin, Governor of North Caro­
lina, to Carroll R. Campbell, Jr., Governor of South Caro­
lina (October 25, 1990)); Statement of Undisputed Mate­
rial Facts ¶¶24–26, 28, 33, 37, 39 (detailing press releases,
gubernatorial letters, and other statements made by
North Carolina expressing its commitment to its Compact
obligations).
   But North Carolina never secured a license, never ob­
tained adequate funding, and never began construction on
a new facility. See Second Report of Special Master 2–3
(hereinafter Second Report). Eventually, the State simply
stopped trying: On December 19, 1997, North Carolina
informed its fellow member States that it would “com­
mence the orderly shutdown” of the waste disposal “pro­
ject.” App. 319. After this point, North Carolina admit­
tedly took no further steps toward obtaining a license or
building a facility before withdrawing from the Compact in
July 1999. Id., at 460 (North Carolina Admissions ¶11
(North Carolina “did not [after 1997] take additional steps
to . . . license a waste disposal facility”)); Second Report 10
(“The parties do not dispute that North Carolina did not
take additional steps to pursue a license for a waste facil­
ity” after December 1997).
   Whatever one might think of the sufficiency of North
Carolina’s activities during the previous decade, I do not
                 Cite as: 560 U. S. ____ (2010)           3

                     Opinion of BREYER, J.

see how the Court can find that a year and a half of doing
nothing—which North Carolina admits it did between
December 1997 and July 1999—constitutes “tak[ing]
appropriate steps.” If a student promises to “take appro­
priate steps to ensure” that he will pass the bar and then
refuses to study, has he not broken his promise? More to
the point, if a builder promises that he will “take appro­
priate steps to ensure” that a customer will be able to
move into a new home in two years, and then does nothing
at all, has the builder not broken his promise?
   As the majority notes, “[o]ther contemporaneously en­
acted interstate compacts” delineated a host State’s obli­
gations in more detail than the Southeast Compact does.
Ante, at 16–17. But this fact may just as easily be read to
indicate what the parties here intended, rather than, as
the majority argues, what they did not intend. Regard­
less, the language of the Compact and the context in which
it was enacted—as part of a congressional effort to en­
courage regional solutions to this Nation’s low-level radio­
active waste problem, see Consent Act, 99 Stat. 1859; Low-
Level Radioactive Waste Policy Act, §4(a)(1), 94 Stat.
3348—both indicate that North Carolina was supposed to
take “appropriate steps” to build a low-level radioactive
waste disposal facility. And North Carolina’s General
Assembly passed a state statute recognizing and accepting
this responsibility. See N. C. Gen. Stat. §104G–4 (creating
a state agency to “site, finance, [and] build” a waste dis­
posal facility). How can it be that two years of inactivity
followed by withdrawal satisfies this promise?
   The answer, says the Court, is that any further “appro­
priate steps” would have cost a significant amount of
money. Ante, at 14–15. In 1997, the Southeast Interstate
Low-Level Radioactive Waste Management Commission
(Commission), the entity responsible for administering the
Compact, made clear that it would not advance North
Carolina any more money toward building a facility. See
4               ALABAMA v. NORTH CAROLINA

                      Opinion of BREYER, J.

App. 315. In response, North Carolina concluded that it
was unwilling to fund the rest of the project itself. See id.,
at 317–319. And the Court agrees that it would have been
“imprudent” for North Carolina to spend further funds, in
light of the Commission’s refusal to do so also. Ante, at
15–16.
   But this is an odd excuse. If a builder promises to “take
appropriate steps” to build me a house, the fact that he
runs out of funds would not normally excuse his breaking
his promise—at least if it is he, and not I, who is responsi­
ble for financing the project. See 2 E. Farnsworth, Con­
tracts §9.6, p. 638 (3d ed. 2004) (Farnsworth) (courts
“generally” conclude that “additional expense” “does not
rise to the level of impracticability” so as to excuse a party
from performance). And here it is North Carolina, and not
anyone else, who bears ultimate responsibility for finding
the funds.
   The text, structure, and purpose of the Compact all
demonstrate this fact. As the Court recognizes, ante, at 2,
the Compact expressly provides that the Commission “is
not responsible for any costs associated with . . . the crea­
tion of any facility,” Art. 4(K)(1), 99 Stat. 1876. Rather,
the Compact States determined that each “party state”
should take a turn as the “host state,” during which time
that State would be obligated to build a facility and then
operate it for 20 years. See Art. 3(A), id., at 1873; Art.
5(A), id., at 1877; Art. 5(C), ibid.; Art. 5(E), 103 Stat. 1289;
see also Art. 3(C), 99 Stat. 1873–1874 (“Host states are
responsible for the availability, the subsequent post­
closure observation and maintenance, and the extended
institutional control of their regional facilities”). The host
State would then recover its upfront construction expenses
from the considerable fees and surcharges charged to the
waste generators served by the facility. N. C. Gen. Stat.
§§104G–15(a)–(b) (repealed 2000) (“It is the intent of the
General Assembly that the cost of all activities [toward
                 Cite as: 560 U. S. ____ (2010)            5

                     Opinion of BREYER, J.

siting, building, and operating a facility] be borne by the
waste generators” who use it); Brief for Plaintiffs in Sur­
reply to North Carolina’s Reply 1, n. 1 (noting that a dis­
posal facility in South Carolina collected over $47 million
in fees in 2008).
   Of course, as the majority notes, South Carolina’s with­
drawal from the Compact could have affected North Caro­
lina’s ability to “recoup” its “construction costs.” Ante, at
18. But, as far as I am aware, North Carolina did not
seriously seek to amend the Compact when South Caro­
lina departed (even though the State had sought and
obtained an amendment previously, see ante, at 20, n. 4;
Brief for North Carolina in Reply to Exceptions By Plain­
tiffs to Reports of the Special Master 27), nor has it argued
to this Court that South Carolina’s departure voided its
contractual obligations. Indeed, there is evidence in the
record indicating that, even after South Carolina left the
Compact, North Carolina continued to believe that the
operation of a waste disposal facility presented a substan­
tial financial opportunity. App. 255, 266 (Attachment to
Letter from John H. MacMillan, Executive Director, North
Carolina Low-Level Radioactive Waste Management
Authority, to Richard S. Hodes, M. D., Chairman, South­
east Compact Commission (Dec. 13, 1996) (enclosing a
business plan identifying $600 million in cost savings that
could provide a “substantial return” on the “investment
needed to put the North Carolina facility into operation”)).
   I thus cannot conclude, as the majority does, that the
Compact’s rotational design, as I understand it, is “fool­
ish.” Ante, at 18. Rather, the Compact’s structure repre­
sents what, in my view, was a understandable decision by
the contracting States, all of whom needed a waste dis­
posal facility, to bind themselves together so that each
would take a turn “bear[ing] the cost of building” the
necessary facility. Preliminary Report of Special Master
21 (citing Art. 4(K), 99 Stat. 1876–1877); see Brief for
6              ALABAMA v. NORTH CAROLINA

                     Opinion of BREYER, J.

Rocky Mountain Low-Level Radioactive Waste Compact
Board et al. as Amici Curiae 16–18. This rotational ap­
proach is surely a sensible solution to the problems caused
by the widespread existence of low-level nuclear waste and
the political unpopularity of building the necessary facili­
ties to house it. See id., at 13–16; New York v. United
States, 505 U. S. 144, 149–151 (1992).
   The only contrary evidence—i.e., that indicates that
North Carolina did not bear ultimate funding responsibil­
ity—consists of the fact that the Commission voluntarily
advanced North Carolina nearly $80 million between 1988
and 1998 in order to help it defray its costs. Second Re­
port 16. The Court believes that this “course of perform­
ance” demonstrates that, once the Commission turned off
its monetary spigot, North Carolina was no longer re­
quired to do anything further. Ante, at 14–15. But why?
If I advance my builder half the cost of a building, I have
not thereby promised to advance him the whole cost. This
is particularly true when the contract says I am responsi­
ble for none of the cost of the building. At the very least,
something more in the circumstances would have to show
that additional expenditure had become a reasonable
expectation.
   In this case, nothing suggests that North Carolina could
reasonably expect further financing assistance. Indeed, I
can find nothing in the majority’s opinion, or the record,
that suggests that the Commission or the other Compact
States intended to let North Carolina off the hook. And
numerous documents indicate precisely the opposite—that
despite the Commission’s funding assistance, North Caro­
lina was still responsible for funding the project. See, e.g.,
App. 63 (Resolution (Feb. 9, 1988) (“The Commission,
although not obligated to do so under the Compact,” pro­
vides funding for North Carolina)); id., at 215 (Letter from
Richard S. Hodes, M. D., Chairman, Southeast Compact
Commission, to James B. Hunt, Governor of North Caro­
                  Cite as: 560 U. S. ____ (2010)             7

                      Opinion of BREYER, J.

lina (Jan. 5, 1996) (“At some point, Commission funds will
no longer be available to North Carolina . . . , and North
Carolina will need to make alternate plans . . .”)); id., at 75
(Press Release by James G. Martin, Governor of North
Carolina (Nov. 8, 1989) (“ ‘The task of siting and operating
a low-level radioactive waste disposal facility is a com­
mitment the state of North Carolina has made and one
which I am personally committed to keeping’ ”)); id., at 92
(Letter from Governor of North Carolina, to Governor of
South Carolina (“North Carolina remains committed to
fulfilling its obligations to the Compact to serve as the
next host state”); id., at 183 (Letter from James B. Hunt,
Jr., Governor of North Carolina, to David M. Beasley,
Governor of South Carolina (Mar. 14, 1995) (“Let me
assure you that North Carolina is committed to honoring
its obligation to the Compact”)); Statement of Undisputed
Material Facts ¶¶28, 33, 39 (other public statements about
North Carolina’s commitment to building a facility).
   Without better evidence of a reallocation of funding
responsibility, I can only conclude that North Carolina
remained under an obligation to “take appropriate steps”
at all times relevant to this case. And North Carolina
admittedly took no steps towards building a disposal facil­
ity from December 1997 and July 1999: It did no in-depth
study of the further financing that might be necessary; it
made no serious effort to look for alternative funding; the
Executive of the State did not ask its legislature for any
appropriation. Rather, North Carolina simply withdrew
from the Compact. Ante, at 5.
   Of course, North Carolina was free to withdraw from the
Compact. Art. 7(G), 99 Stat. 1879–1880. But that fact
does not repair what, in my view, was a breach of a key
contractual provision. See Franconia Associates v. United
States, 536 U. S. 129, 142–143 (2002) (“Failure by the
promisor to perform . . . establishes an immediate breach”);
Restatement (Second) of Contracts §235(2) (1979) (“When
8             ALABAMA v. NORTH CAROLINA

                   Opinion of BREYER, J.

performance of a duty under a contract is due any non
performance is a breach” (emphasis added)); 2 Farnsworth
§8.8, at 471.
  With respect, I dissent.
