 United States Court of Appeals
         FOR THE DISTRICT OF COLUMBIA CIRCUIT



Argued November 20, 2012           Decided February 8, 2013

                        No. 11-7018

    ERIC SHEPTOCK AND COMMITTEE TO SAVE FRANKLIN
          SHELTER, ON BEHALF OF ITS MEMBERS,
                     APPELLANTS

                             v.

ADRIAN FENTY, IN HIS INDIVIDUAL AND OFFICIAL CAPACITIES,
                         ET AL.,
                       APPELLEES


        Appeal from the United States District Court
                for the District of Columbia
                    (No. 1:09-cv-00672)


     George E. Rickman argued the cause and filed the briefs
for appellants.

    Stacy L. Anderson, Assistant Attorney General, Office of
the Attorney General for the District of Columbia, argued the
cause for appellees. With her on the brief were Irvin B.
Nathan, Attorney General, Todd S. Kim, Solicitor General,
and Donna M. Murasky, Deputy Solicitor General.

   Before: ROGERS and TATEL, Circuit Judges, and
EDWARDS, Senior Circuit Judge.
                                2
    Opinion for the Court filed by Circuit Judge TATEL.

     TATEL, Circuit Judge: This case stems from the closure
of the Franklin Shelter, an overnight facility for homeless men
in downtown Washington, D.C. In two prior suits filed in the
Superior Court for the District of Columbia, former shelter
residents alleged that the closure violated D.C. law and the
Fifth Amendment to the United States Constitution. In a third
case, filed in federal court and on appeal here, plaintiffs allege
that the closure also violated federal and D.C.
antidiscrimination statutes. Because plaintiffs could have
raised these latter claims in the Superior Court cases, we
affirm the district court’s dismissal on res judicata grounds.

                                I.
     At the time the Franklin Shelter was operating,
approximately 2,200 single adults were chronically homeless
in the District of Columbia. See Second Am. Fed. Compl.
¶ 20; see also Nader v. Democratic National Committee, 567
F.3d 692, 694 (D.C. Cir. 2009) (“Because the district court
granted defendants’ motion to dismiss, [plaintiffs’] allegations
must be taken as true.” (internal quotation marks omitted)).
Because the Franklin Shelter served as an emergency facility,
residents were permitted to stay there only between 4 P.M.
and 7 A.M. Although required to leave during the day,
residents could keep their personal belongings in small
lockers. Mirroring the District’s homeless population,
Franklin Shelter residents were disproportionately African
American. See Second Am. Fed. Compl. ¶¶ 20, 28. Many
suffered from psychological disorders and substance abuse
problems. See id. ¶¶ 24, 28.

    In mid-2008, Mayor Adrian Fenty and the D.C. City
Council began making plans to close the Franklin Shelter. On
September 16, the City Council passed the Franklin Shelter
                                3
Closing Requirements Emergency Act of 2008, which
required the mayor to make certain detailed certifications
before closing the facility. See D.C. Act 17-518. Before
signing the Emergency Act, however, the Mayor closed the
shelter and made none of the required certifications. See
Second Am. Fed. Compl. ¶¶ 14–16.

     Evicted residents were informed that their personal
belongings had been moved to a homeless shelter in
Anacostia and that they could receive transportation there if
they wished. They were also encouraged to relocate to
shelters outside Northwest Washington—the city’s rapidly
gentrifying commercial and residential area. See id. ¶¶ 14, 28,
33–37. And to “mitigate any loss of shelter space,” id. ¶ 38,
the District created the Permanent Supportive Housing
Program to provide long-term housing and services to the
chronically homeless.

    The Franklin Shelter closing sparked a flurry of litigation.
Specifically, former Franklin Shelter residents—including
named plaintiff Eric Sheptock—and the Committee to Save
Franklin Shelter brought three separate suits, two in D.C.
Superior Court and one in the United States District Court for
the District of Columbia. Because the outcome of this case
turns on the application of res judicata, we describe each of
these suits in detail.

     The first case, Sheptock I, was filed in D.C. Superior
Court on September 26, 2008, the day the Franklin Shelter
closed. Plaintiffs brought two D.C. law claims, as well as a
Fifth Amendment procedural due process claim premised on
the District’s failure to provide advance notice and an
opportunity to be heard before closing the shelter. Shortly
after initiating the case, plaintiffs filed a notice of dismissal,
which terminated the suit.
                               4
     While Sheptock I was pending, plaintiffs filed a second
suit, Sheptock II, in D.C. Superior Court. The Sheptock II
plaintiffs raised eight claims: a Fifth Amendment procedural
due process claim; a Takings Clause challenge to the
appropriation of the former residents’ personal belongings;
intentional infliction of emotional distress; conversion;
negligence; and violations of the Emergency Act, the Frigid
Temperature Protection Amendment Act of 1988, D.C. Code
§ 4-753.01, and the Homeless Services Reform Act of 2005,
D.C. Code § 4-754.22. Plaintiffs twice amended their
complaint to add new facts and allegations concerning the
fallout from the Franklin Shelter closure.

     Significantly for our purposes, on March 9, 2009, the
Sheptock II plaintiffs filed a motion entitled “Motion to Stay
Proceedings Pending Discovery and Pending Submission of
Federal Claims in the United States District Court for the
District of Columbia or in the Alternative Motion to Amend
Complaint for Preliminary and Permanent Injunctions.” In
this motion, plaintiffs notified the Superior Court that they
would be bringing claims in federal court under the
Americans with Disabilities Act (ADA), 42 U.S.C. §§ 12101
et seq., the Fair Housing Act (FHA), 42 U.S.C. §§ 3601 et
seq., and the D.C. Human Rights Act, D.C. Code §§ 2-
1401.01 et seq. According to plaintiffs, further investigation
had uncovered evidence concerning the Franklin Shelter’s
racial demographics and the widespread presence of
disabilities in the homeless community. Based on these facts,
plaintiffs alleged race and disability discrimination under
theories of disparate treatment and disparate impact. Plaintiffs
“move[d] [the Superior Court] to stay proceedings on
defendant’s motion for dismissal or summary judgment . . .
pending plaintiffs’ submission of federal [antidiscrimination]
claims” in federal court. The motion included a seventeen-
page discussion of the merits of plaintiffs’ antidiscrimination
                               5
claims. Acknowledging that the Superior Court had
jurisdiction to hear their federal antidiscrimination claims,
plaintiffs nonetheless asserted that “[w]hile the splitting of
claims is disfavored, the federal claims raised here are ones of
a special nature and are claims of first impression, and
warrant federal jurisdiction.” In the alternative, plaintiffs
moved to amend their complaint, attaching a third amended
complaint that included the ADA, FHA, and D.C. Human
Rights Act claims. Plaintiffs subsequently withdrew that
request, reserving the right to re-file an amended complaint.

     On May 11, 2009, the Superior Court granted the
District’s motion for summary judgment and denied all other
pending motions, including plaintiffs’ motion to stay. A year
and a half later, the D.C. Court of Appeals affirmed. See
Baltimore v. District of Columbia, 10 A.3d 1141 (D.C. 2011).
In a footnote, the Court of Appeals held that the Superior
Court had not abused its discretion in denying the motion to
stay and that the antidiscrimination claims “could have been
filed in the instant action and [plaintiffs] offer no persuasive
reason why they were not.” Id. at 1156 n.23.

     While Sheptock II was pending in the D.C. Superior
Court, plaintiffs initiated their third suit, Sheptock III, by
filing a complaint in the United States District Court alleging
violations of the ADA, FHA, and D.C. Human Rights Act.
The Sheptock III plaintiffs also alleged procedural and
substantive due process violations. Unlike in Sheptock II,
plaintiffs brought no claims under the Takings Clause, the
Emergency Act, or D.C. tort law. The Sheptock III plaintiffs
named as defendants then-Mayor Fenty and three other
officials, each in their individual and official capacities.

    In early July 2009, the district court, responding to a
motion to dismiss based on res judicata, stayed Sheptock III
                               6
“pending a decision by the District of Columbia Court of
Appeals in a matter arising out of the same event that is the
subject of this litigation.” At the same time, the district court
permitted plaintiffs to file a second amended complaint that
added antidiscrimination counts challenging the District’s
Permanent Supportive Housing Program. As set forth in that
complaint, plaintiffs’ claims can be divided into three
categories: Counts I through X allege that the Franklin Shelter
closure violated the ADA, FHA, and D.C. Human Rights Act;
Counts XI and XII allege that the closure violated plaintiffs’
procedural and substantive due process rights; and Counts
XIII through XVIII allege that the Permanent Supportive
Housing Program violates the ADA, FHA, and D.C. Human
Rights Act. After the D.C. Court of Appeals issued its
decision in Sheptock II, the district court dismissed Sheptock
III on res judicata and collateral estoppel grounds.

     The Sheptock III plaintiffs raise two arguments on appeal.
First, they contend that the motion to stay filed in Sheptock II
insulates their claims from res judicata. Second, insisting that
their challenges to the closure of the Franklin Shelter and to
the District’s Permanent Supportive Housing Program are
factually distinct, plaintiffs contend that Counts XIII through
XVIII fall outside Sheptock II’s preclusive effect. “We review
a dismissal for failure to state a claim under Federal Rule of
Civil Procedure 12(b)(6) de novo.” Atherton v. D.C. Office of
the Mayor, 567 F.3d 672, 681 (D.C. Cir. 2009). Similarly, we
review the application of res judicata de novo. See Ibrahim v.
District of Columbia, 463 F.3d 3, 7 (D.C. Cir. 2006).

                               II.
     We begin with familiar principles. “The federal courts
have traditionally adhered to the . . . doctrine[] of res
judicata.” Allen v. McCurry, 449 U.S. 90, 94 (1980). Under
that doctrine, also known as claim preclusion, “a final
                                7
judgment on the merits . . . precludes relitigation in a
subsequent proceeding of all issues arising out of the same
cause of action between the same parties or their privies,
whether or not the issues were raised in the first trial.”
Faulkner v. GEICO, 618 A.2d 181, 183 (D.C. 1992)
(emphasis added). For res judicata purposes, a “ ‘cause of
action’ is determined by the factual nucleus, not the theory on
which a plaintiff relies.” Id. (internal quotation marks
omitted). “If there is a common nucleus of facts, then the
actions arise out of the same cause of action.” Id. “In
determining whether the two actions arise out of the same
cause of action, [courts] consider[] the nature of the two
actions and the facts sought to be proved in each one.” Id.
(internal quotation marks omitted). Res judicata serves “the
dual purpose of protecting litigants from the burden of
relitigating an identical issue with the same party or his privy
and of promoting judicial economy by preventing needless
litigation.” Parklane Hosiery Co. v. Shore, 439 U.S. 322, 326
(1979).

     Less familiar in this Circuit is the related doctrine of
abstention. Cf. John G. Roberts, Jr., What Makes the D.C.
Circuit Different? A Historical View, 92 Va. L. Rev. 375,
387–88 (2006) (noting the rarity of state law cases in the D.C.
Circuit and detailing the creation of the District of Columbia’s
local court system in the 1970s). Under that doctrine, “a
District Court may decline to exercise or postpone the
exercise of its jurisdiction.” Allegheny County v. Frank
Mashuda Co., 360 U.S. 185, 188 (1959). But as with many
legal concepts, abstention, as this case well illustrates, “is not
one doctrine but several.” Adrian Energy Associates v.
Michigan Public Service Commission, 481 F.3d 414, 423 (6th
Cir. 2007).
                                8
    Plaintiffs contend that this case is governed by the
abstention principles articulated in Railroad Commission of
Texas v. Pullman Co., 312 U.S. 496 (1941). There, a group of
African American porters and the Pullman railroad company
brought a constitutional challenge in federal court against a
Texas regulation mandating that Pullman sleeping cars always
have at least one conductor—which at the time meant a white
conductor. The Supreme Court recognized that this complaint
“undoubtedly tendered a substantial constitutional issue. . . . It
touches a sensitive area of social policy upon which the
federal courts ought not to enter unless no alternative to its
adjudication is open.” Id. at 498. The Court further explained
that it would be unnecessary to reach the constitutional
question if the Texas Railroad Commission lacked authority
under state law to promulgate the challenged regulation.
Accordingly, the Court endorsed a “doctrine of abstention”
whereby a federal court must withhold ruling on a federal
claim so that plaintiffs may obtain a state court ruling on an
antecedent state law question. Id. at 501. Given preclusion
doctrine, Pullman abstention raises the question—central to
the Sheptock III plaintiffs’ argument—of how parties
compelled to litigate their state law claims in state court can
protect their right to return to federal court.

     The Supreme Court answered this question in England v.
Louisiana State Board of Medical Examiners, 375 U.S. 411
(1964), where it fashioned a mechanism—known as an
England reservation—by which parties forced into state court
by federal court abstention can reserve their federal claims
and avoid the preclusive effect of a state court judgment. The
England plaintiffs wanted to practice in Louisiana without
satisfying the educational requirements of the Louisiana
Medical Practice Act. They first brought suit in federal court
seeking to have the Act invalidated under the Fourteenth
Amendment. Invoking Pullman abstention, the federal court
                                9
entered an order staying proceedings and retaining
jurisdiction pending resolution of a state law question in a
Louisiana state court. Plaintiffs then brought suit in state court
and “did not restrict those proceedings to the question
whether the Medical Practice Act applied to chiropractors.
They unreservedly submitted for decision, and briefed and
argued, their contention that the Act, if applicable to
chiropractors, violated the Fourteenth Amendment.” Id. at 413
(footnote omitted). After losing both claims in the Louisiana
courts, they returned to federal court and the issue of res
judicata came to the fore.

     In considering this issue, the Supreme Court expressed a
“fundamental objection[] to any conclusion that a litigant who
has properly invoked the jurisdiction of a Federal District
Court to consider federal constitutional claims can be
compelled, without his consent and through no fault of his
own, to accept instead a state court’s determination of those
claims.” Id. at 415 (footnote omitted). The Court also
acknowledged that in the “typical” abstention case—“where
the state courts are asked to construe a state statute against the
backdrop of a federal constitutional challenge,” id. at 420—
plaintiffs may feel compelled to alert the state court to the
pending federal challenge to fully argue their case. Indeed, in
Government and Civic Employees Organizing Committee v.
Windsor, 353 U.S. 364 (1957), the Court had required
plaintiffs to notify a state court about pending claims in
federal court. Thus, to avoid res judicata, the England Court
instructed plaintiffs to put

    on the state record the reservation to the disposition
    of the entire case by the state courts . . . . That is,
    [plaintiff] may inform the state courts that he is
    exposing his federal claims there only for the
    purpose of complying with Windsor, and that he
                               10
    intends, should the state courts hold against him on
    the question of state law, to return to the District
    Court for disposition of his federal contentions.

England, 375 U.S. at 421 (internal quotation marks omitted).
In other words, if a party asks a state court not to adjudicate
its federal claims because it intends to return to federal court,
then it can escape the preclusive effect of a state court
judgment. Conversely, “if a party freely and without
reservation submits his federal claims for decision by the state
courts, litigates them there, and has them decided there, then
. . . he has elected to forgo his right to return to the District
Court.” Id. at 419.

     Assuming, as plaintiffs insist, that the district court
stayed the case under Pullman, the parties contest whether a
litigant must first file suit in federal court to obtain an
England reservation—a question that has sparked a circuit
split. Compare United Parcel Service v. California Public
Utilities Commission, 77 F.3d 1178, 1185 (9th Cir. 1996)
(“[W]e decline to limit England’s application to cases where
the litigant files first in federal court and is remitted to state
court pursuant to Pullman.”), with Fuller Co. v. Ramon I. Gil,
Inc., 782 F.2d 306, 312 (1st Cir. 1986) (“In order to make an
England reservation, a litigant must establish its right to have
its federal claims adjudicated in a federal forum by properly
invoking the jurisdiction of the federal court in the first
instance.”). The parties also disagree about whether the
Supreme Court’s decisions in Williamson County Regional
Planning Commission v. Hamilton Bank of Johnson City, 473
U.S. 172 (1985), and San Remo Hotel v. City and County of
San Francisco, 545 U.S. 323 (2005), required the Sheptock II
plaintiffs to litigate their Takings Clause claim in D.C.
Superior Court.
                               11
     More fundamentally, the District of Columbia disagrees
with plaintiffs’ contention that the district court stayed the
case under Pullman abstention principles. According to the
District, the court stayed the case pursuant to Colorado River
Water Conservation District v. United States, 424 U.S. 800
(1976), which allows a district court to abstain “due to the
presence of a concurrent state proceeding.” Id. at 818.
Premised on “reasons of wise judicial administration,” id.,
Colorado River abstention “does not rest on a mechanical
checklist, but on a careful balancing of . . . important factors.”
Moses H. Cone Memorial Hospital v. Mercury Construction
Corp., 460 U.S. 1, 16 (1983). These considerations include
which court “first assum[ed] jurisdiction over property”
involved in the case; “the inconvenience of the federal forum;
the desirability of avoiding piecemeal litigation; and the order
in which jurisdiction was obtained by the concurrent forums.”
Colorado River, 424 U.S. at 818 (internal citations omitted).
As the District sees it, Colorado River governs because
Sheptock III was stayed pending the appeal in Sheptock II. An
England reservation, the District further argues, has no place
when a case is stayed pursuant to Colorado River abstention.

     Fortunately for us, this is not a federal courts exam, and
we have no need to pass on all of these arguments. For even
assuming that plaintiffs are correct about Pullman, their
motion to stay failed to qualify as an adequate England
reservation. In that motion, plaintiffs asked the Superior Court
to “stay proceedings on defendant’s motion for dismissal or
summary judgment . . . pending plaintiffs’ submission of
federal [antidiscrimination] claims” in federal court. In plain
English, plaintiffs asked the Superior Court to stay all
pending claims, both D.C. and federal. This was not an
England reservation. Under England, a party asks the state
court to resolve an antecedent state law issue so that it can
return to federal court and have its federal claims heard. Here,
                                12
by contrast, the Sheptock II plaintiffs asked the Superior Court
to stay all claims and never signaled a desire to proceed in
federal court after the Superior Court ruled on any claim,
much less an antecedent question of D.C. law.

     Reinforcing our view that plaintiffs’ motion to stay fails
to qualify as an England reservation, the parties’ briefs on that
motion repeatedly frame the issue as one of removal. See 28
U.S.C. §§ 1441 & 1446 (removal jurisdiction). In fact, the
briefs make no reference at all to England. In opposing the
motion to stay, the District was uncertain as to what plaintiffs
had actually requested of the Superior Court. “It is not clear,”
the District wondered, “whether plaintiffs seek some sort of
bifurcation or removal of claims plaintiffs initiated before this
Court.” Indeed, the Sheptock II plaintiffs took inconsistent
and incoherent positions in their reply brief. Although they
claimed that they were not seeking removal under 28 U.S.C.
§ 1441, they nonetheless framed their request as a “removal”
of their antidiscrimination claims—claims never formally
filed in Superior Court. Plaintiffs also disavowed “removal”
of “previously pending claims,” which included claims under
the Fifth Amendment. On this point, the Sheptock II plaintiffs
appear to have contradicted their own motion, in which they
sought to stay all claims. Given this confusion, it is difficult to
ascertain what exactly the Sheptock II plaintiffs were seeking
in their motion to stay. But what is clear is that plaintiffs
themselves appear not to have believed they were filing an
England reservation.

                               III.
     Plaintiffs acknowledge that absent a valid England
reservation, Counts I through XII are precluded. See Oral Arg.
Rec. 6:55–7:40, 16:49–17:05. These counts include the ADA,
FHA, D.C. Human Rights Act, and due process claims tied
directly to the Franklin Shelter closure.
                             13
     Plaintiffs insist that Counts XIII through XVIII are not
barred by res judicata because they stem from a nucleus of
facts distinct from Sheptock II. These counts raise race and
disability discrimination claims under the ADA and FHA.
Although it is not entirely clear from their second amended
federal complaint, plaintiffs contend that these counts
challenge the District of Columbia’s continuing failure to
provide housing for the homeless in the wake of the Franklin
Shelter closure. Specifically, they point to the District’s
failure to adequately implement its Permanent Supportive
Housing Program. To the extent this program has been
implemented, plaintiffs contend that the District has done so
in a discriminatory fashion and with the goal of moving the
homeless population to the “poorest and most violent parts of
town.” Second Am. Fed. Compl. ¶ 39. According to plaintiffs,
these “post-judgment events give rise to new claims, so that
claim preclusion is no bar.” Stanton v. District of Columbia
Court of Appeals, 127 F.3d 72, 78 (D.C. Cir. 1997); see also
Drake v. FAA, 291 F.3d 59, 67 (D.C. Cir. 2002) (“The [res
judicata] doctrine does not bar a litigant from doing in the
present what he had no opportunity to do in the past.”).

     To recap, res judicata bars a subsequent suit “involving
the same parties or their privies based on the same cause of
action.” Parklane Hosiery Co., 439 U.S. at 326 n.5. To
ascertain if “two cases implicate the same cause of action” we
look to whether “they share the same ‘nucleus of facts.’ ”
Drake, 291 F.3d at 66 (quoting Page v. United States, 729
F.2d 818, 820 (D.C. Cir. 1984)).

    Contrary to plaintiffs’ argument, Counts XIII through
XVIII flow directly from the closure of the Franklin Shelter,
the same event that formed the basis of Sheptock II. The
second amended federal complaint’s factual allegations
repeatedly link the Permanent Supportive Housing Program
                               14
and the closure of the Franklin Shelter. For example, the
complaint alleges that the harms associated with the
Permanent Supportive Housing Program impact “[m]any
former residents of Franklin Shelter.” Second Am. Fed.
Compl. ¶ 42; see also id. ¶ 38 (“The Permanent Supportive
Housing Program, previously identified by the District as the
means to mitigate any loss of shelter space because for [sic]
the closing of Franklin Shelter, fails to keep pace with the
demand.”). The complaint further asserts that the
discriminatory provision of services continues because the
Franklin Shelter remains closed. “Since the closing of
Franklin Shelter,” the complaint alleges, “defendants’
repeated failures directly and proximately denied plaintiffs
needed services.” Id. ¶ 148; see also id. ¶ 117 (“Defendants
intentionally denied plaintiffs housing, continued failures [sic]
to provide adequate shelter space and placement in permanent
supportive housing, because of plaintiffs’ race.”). Indeed, the
requested relief—the reopening of the Franklin Shelter—
demonstrates that the allegedly discriminatory provision of
services is inextricably tied to the Franklin Shelter closure.
See id. ¶ 40 (“Plaintiffs seek temporary and permanent
injunctive relief compelling the District Government to re-
open Franklin Shelter and return the status quo . . . .”).

     To be sure, the events alleged in Counts XIII through
XVIII occurred after the Franklin Shelter was closed. But a
quick glance at the Sheptock II complaint confirms that the
events now alleged in Sheptock III were known to plaintiffs
during the Sheptock II litigation. For one thing, the second
amended complaint refers to the Permanent Supportive
Housing Program’s inability to keep up with demand. See,
e.g., Second Am. D.C. Compl. ¶ 86 (“It is also unclear what
priorities were used to determine placement in the Permanent
Supportive Housing Initiative, since the most vulnerable of
the Franklin Shelter inhabitants are not currently part of the
                              15
program, but are now sleeping in the parks and streets near
Franklin Shelter.”). The complaint also alludes to the
District’s alleged policy of moving the homeless population
out of the downtown commercial area. See, e.g., id. ¶ 80
(“Currently designated warming centers are as many as five
miles away from the downtown area . . . .”); id. ¶ 84 (“Most
placements are occurring in the poorest and most violent parts
of town, and with the least services available for the
vulnerable and the homeless.”). And most significantly, the
complaint acknowledges the disproportionate rates of
substance abuse and mental illness amongst the city’s
homeless population—a key premise of the Sheptock III
plaintiffs’ disability discrimination claims. See id. ¶ 94 (“In
DC, an estimated 71% of the homeless individuals suffer from
either substance abuse or mental illnesses.”).

     Counts XIII through XVIII thus share the same nucleus
of facts as Sheptock II. True, the Sheptock II plaintiffs
marshaled these facts in support of constitutional and D.C.
law claims, rather than antidiscrimination claims. But res
judicata turns on a suit’s factual context, “not the theory on
which a plaintiff relies.” Faulkner, 618 A.2d at 183 (internal
quotation marks omitted). Because these claims “could have
been raised” in Sheptock II, they are precluded. Allen, 449
U.S. at 94.

                             IV.
    For the foregoing reasons, we affirm.

                                                   So ordered.
