                    FOR PUBLICATION
  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT

KARL ERIC GRATZER,                             No. 03-35613
            Petitioner-Appellant,
              v.                                 D.C. No.
                                               CV-87-04-H-CCL
MIKE MAHONEY, WARDEN,*
                                                  OPINION
            Respondent-Appellee.
                                          
         Appeal from the United States District Court
                 for the District of Montana
         Charles C. Lovell, District Judge, Presiding

                  Argued and Submitted
           December 7, 2004—Seattle, Washington

                     Filed January 31, 2005

     Before: Jerome Farris, Michael Daly Hawkins, and
          M. Margaret McKeown, Circuit Judges.

                     Opinion by Judge Farris




  *The parties have agreed to substitute Mike Mahoney for Henry Risley
as Respondent-Appellee, pursuant to Fed. R. App. P. 43(c)(2).

                                1251
                   GRATZER v. MAHONEY               1253


                      COUNSEL

Michael Donahoe, Assistant Federal Defender, Helena, Mon-
tana, for the petitioner-appellant.
1254                 GRATZER v. MAHONEY
Carol E. Schmidt, Assistant Attorney General, Helena, Mon-
tana, for the respondent-appellee.


                         OPINION

FARRIS, Circuit Judge:

   Karl Eric Gratzer appeals the district court’s denial of his
petition for habeas corpus, claiming that a jury instruction in
his 1982 trial in Montana for deliberate homicide violated his
constitutional right to due process. We affirm.

                      BACKGROUND

   The facts underlying Gratzer’s conviction for deliberate
homicide are recounted at State v. Gratzer, 682 P.2d 141
(Mont. 1984); a summary suffices for our purposes. In
December of 1981, the relationship between Gratzer and his
then-girlfriend was deteriorating and Gratzer began to suspect
that his girlfriend was interested in another man, Timothy
Hull. On the evening of April 14, 1982, Gratzer discovered
his girlfriend’s car near a dormitory of the Montana College
of Mineral Science and Technology; his girlfriend did not live
in the dormitory. Gratzer was observed letting the air out of
two tires of the car and was chased away by the observers.

   Gratzer returned to the parking lot armed with a .357 mag-
num pistol. He saw his girlfriend exit the dormitory, discover
the flat tires, and reenter the dormitory. She came out of the
dormitory hand-in-hand with Hull. As they approached the
car, Gratzer confronted them with gun in hand. Gratzer and
Hull struggled and Hull broke free and attempted to flee. As
Hull retreated, Gratzer shot him in the back of the left leg,
incapacitating him. Gratzer walked to the place where Hull
lay and shot him twice, at point blank range, in the left side
of the head. Hull died instantaneously. Gratzer left the scene
and subsequently turned himself in to the police.
                    GRATZER v. MAHONEY                       1255
   On April 20, 1982, Gratzer was charged with Deliberate
Homicide and Aggravated Assault. At his trial, Gratzer pres-
ented expert testimony that he was acting under severe emo-
tional stress at the time of the murder. As a result of this
testimony, the judge gave the jury the following instruction,
No. 10A, as to the offense of Mitigated Deliberate Homicide,
a lesser included offense of Deliberate Homicide:

    In order to find the Defendant Guilty of the lesser
    offense of mitigated deliberate homicide, the State
    must prove the following propositions:

    First, that the Defendant performed the acts causing
    the death of Tim Hull, and

  Second, that when the Defendant did so, he acted purposely
or knowingly.

    Additionally, you must find that at the time the
    Defendant killed [Hull], he was acting under the
    influence of extreme mental or emotional stress for
    which there is reasonable explanation or excuse. The
    reasonableness of such explanation or excuse shall
    be determined from the viewpoint of a reasonable
    person in the Defendant’s situation.

    If you find from your consideration of all the evi-
    dence that each of the first two propositions has been
    proved beyond a reasonable doubt by the State and
    that the Defendant, at the time he killed [Hull], was
    acting under the influence of extreme mental or emo-
    tional stress for which there is reasonable explana-
    tion or excuse, then you should find the Defendant
    Guilty of the lesser offense of Mitigated Deliberate
    Homicide.

    However, if you find that the Defendant was not act-
    ing under the influence of extreme mental or emo-
1256                     GRATZER v. MAHONEY
      tional stress for which there is a reasonable
      explanation or excuse, then you should find the
      Defendant Guilty of Deliberate Homicide.

      If you find from your consideration of all the evi-
      dence that either of the first two propositions has not
      been proven by the State beyond a reasonable doubt,
      then you must find the Defendant Not Guilty of
      Deliberate Homicide.

   The jury convicted Gratzer of Deliberate Homicide and
acquitted him of Aggravated Assault. Gratzer was sentenced
to life imprisonment plus ten years for the use of a firearm in
the commission of the offense. Gratzer appealed to the Mon-
tana Supreme Court, challenging Jury Instruction No. 10A,
and the Montana Supreme Court affirmed his conviction.
Gratzer, 682 P.2d at 148.

   On January 13, 1987, Gratzer filed a petition for habeas
corpus in the federal district court of Montana, again chal-
lenging Instruction No. 10A. On October 10, 1990, the district
court adopted the magistrate judge’s recommendation that the
State’s motion for summary judgment be granted. Gratzer
filed a notice of appeal and a request for a certificate of proba-
ble cause in the district court on October 16, 1990, which the
court denied on November 9, 1990. On November 19, 1990,
Gratzer filed a request for issuance of a certificate of probable
cause with this Court. He contacted this Court on January 27,
1992, seeking the docket sheet reflecting his appeal, but the
Court informed Gratzer that his submissions did not appear to
meet the filing requirements.1

  Gratzer did nothing for more than eleven years. On June
30, 2003, he requested a certificate of appealability from this
Court, which was granted on the issues of whether the amend-
  1
   There is nothing in the record that clarifies the problem with Gratzer’s
submission to this Court in 1990.
                     GRATZER v. MAHONEY                   1257
ments to the Antiterrorism and Effective Death Penalty Act
apply to his case and whether his constitutional rights were
violated by Instruction No. 10A.

                       DISCUSSION

   Before addressing the merits of Gratzer’s petition, we
resolve two preliminary matters: the rules and standards gov-
erning our review of Gratzer’s petition; and whether the equi-
table doctrine of laches bars the petition.

       Standard of Review Applicable to the Petition

   [1] The determination of whether AEDPA applies to a
habeas petition is reviewed de novo. United States v. Villa-
Gonzalez, 208 F.3d 1160, 1163 (9th Cir. 2000). Gratzer’s
original petition for habeas corpus was filed in 1987, and the
AEDPA amendments’ effective date is April 24, 1996. Pre-
AEDPA law applies to the merits of Gratzer’s petition. See
Phillips v. Woodford, 267 F.3d 966, 973 (9th Cir. 2001).

   The Supreme Court has held that AEDPA’s provisions
regarding the issuance of a COA as a predicate to review in
the court of appeals apply to all cases in which the notice of
appeal was filed after AEDPA’s effective date. Slack v.
McDaniel, 529 U.S. 473, 482 (2000). Gratzer’s notice of
appeal was filed on October 16, 1990, well before the
AEDPA amendments took effect; therefore pre-AEDPA prac-
tice applies, and the granting of a COA by this Court was, as
a technical matter, improper. However, the amendment to 28
U.S.C. § 2253 merely codified the pre-AEDPA standard for
obtaining a certificate of probable cause set forth in Barefoot
v. Estelle, 463 U.S. 880, 893-94 (1983). Tillman v. Cook, 215
F.3d 1116, 1120 (10th Cir. 2000). The technical error of issu-
ing a COA, as opposed to a CPC, is therefore immaterial.

                           Laches

   [2] In pre-AEDPA practice, the equitable doctrine of laches
as applicable to habeas petitions was codified in Rule 9(a) of
1258                 GRATZER v. MAHONEY
the Rules Governing Section 2254 Cases. Harris v. Pulley,
885 F.2d 1354, 1365-66 (9th Cir. 1988). Rule 9(a) provided:

    A petition may be dismissed if it appears that the
    state of which the respondent is an officer has been
    prejudiced in its ability to respond to the petition by
    delay in its filing unless the petitioner shows that it
    is based on grounds of which he could not have had
    knowledge by the exercise of reasonable diligence
    before the circumstances prejudicial to the state
    occurred.

The State argues that it has been prejudiced by Gratzer’s
eleven-year delay in bringing this appeal because it is virtu-
ally impossible to re-prosecute him now for a crime that
occurred over twenty years ago. The record reflects a basis for
this argument. Nevertheless, the relevant standard is whether
the State has been prejudiced in its ability to respond to the
issues raised by the petition, Aiken v. Spalding, 684 F.2d 632,
634 (9th Cir. 1982), not in its ability to retry the defendant.
Vasquez v. Hillery, 474 U.S. 254, 265 (1986). Under pre-
AEDPA standards, neither the petitioner’s substantial and
unwarranted delay in filing the petition nor the difficulty of
re-prosecution is dispositive — only the prejudice to the state
in responding to the issues in the petition is material. Aiken,
684 F.2d at 634.

   [3] The question is whether Instruction No. 10A violated
Gratzer’s constitutional rights. The State has not demonstrated
that Gratzer’s delay in raising this question has prejudiced its
ability to respond adequately; the petition will not be dis-
missed on the basis of laches.

                          The Merits

   Under pre-AEDPA law, we review questions of law raised
in habeas cases de novo. Williams v. Taylor, 529 U.S. 362,
400 (2000) (O’Connor, J., concurring in part). Petitioner’s
                         GRATZER v. MAHONEY                           1259
sole constitutional contention is that his due process rights
were violated because Jury Instruction No. 10A either (1)
improperly imposed the burden of proving mitigation on him,
or (2) did not assign the burden of proving extreme mental or
emotional stress to either party.2

   [4] The State charged Gratzer with Deliberate Homicide.
To convict for Deliberate Homicide in 1982, the State was
required to prove beyond a reasonable doubt that one pur-
posely or knowingly caused the death of another human
being. Mont. Code Ann. § 45-5-102 (1981). Under Montana
law at the time, “knowledge or purpose may be inferred from
the fact that the accused committed a homicide and no cir-
cumstances of mitigation, excuse or justification appears.”
Mont. Code Ann. § 46-16-203(2) (1982).3

   The State did not charge Mitigated Deliberate Homicide. In
1982, Montana’s Mitigated Deliberate Homicide statute stated
in relevant part:
     Criminal homicide constitutes mitigated deliberate
     homicide when a homicide which would otherwise
     be deliberate homicide is committed under the influ-
     ence of extreme mental or emotional stress for which
     there is reasonable explanation or excuse . . . .
Mont. Code Ann. § 45-5-103(1) (1982).
   In Gratzer’s appeal, the Montana Supreme Court stated that
neither party has the burden of proof as to mitigating circum-
stances, but either party may present evidence of mitigation.
Gratzer, 682 P.2d at 146. That statement of law has subse-
  2
     At no point in his briefing does Gratzer claim that the failure of Jury
Instruction No. 10A to instruct the jury as to the quantum of proof neces-
sary to establish extreme mental or emotional stress violated his constitu-
tional rights. At oral argument, counsel for Gratzer explicitly disavowed
such a claim.
   3
     This statement was not included in Instruction No. 10A.
1260                      GRATZER v. MAHONEY
quently been codified at Mont. Code Ann. § 45-5-103(3)
(2003).4
   [5] Gratzer argues first that Instruction No. 10A imposed
the burden of proving mitigation on him, thereby improperly
relieving the prosecution of its burden to prove the absence of
mitigating circumstances. This contention must be rejected.
The State charged Gratzer with Deliberate Homicide. The
existence of extreme mental or emotional stress is not an ele-
ment of that offense. It is nonsensical to argue that the State
should have been required to prove anything other than the
elements of Deliberate Homicide in order to obtain a convic-
tion for that crime. The elements in the Montana statute dis-
tinguish this case from United States v. Marolda, 615 F.2d
867 (9th Cir. 1980), upon which Gratzer purports to rely.
There, the government charged Marolda with embezzling
from a labor union and the jury convicted him of that offense.
Id. at 868. One of the facts underlying the charge was Marol-
da’s alleged improper use of a credit card for unauthorized
charges. Id. We held that it was error for the district court to
instruct the jury that it need not decide whether Marolda’s use
of the credit card was properly authorized. Id. at 870-71. By
contrast, the State did not charge that Gratzer acted in the
absence of extreme mental or emotional stress; it charged
only that Gratzer committed Deliberate Homicide, whose ele-
  4
    States are not required to provide affirmative defenses or mitigating
circumstances, and may define which party bears the burden of proof for
such defenses and circumstances. See Patterson v. New York, 432 U.S.
197, 209 (1977) (“If the State . . . chooses to recognize a factor that miti-
gates the degree of criminality or punishment, we think the State may
assure itself that the fact has been established with reasonably [sic] cer-
tainty. To recognize at all a mitigating circumstance does not require the
State to prove its nonexistence in each case in which the fact is put in
issue, . . . .” ); Martin v. Ohio, 480 U.S. 228, 232 (1987) (“[In Patterson,
we] emphasized the preeminent role of the States in preventing and deal-
ing with crime and the reluctance of the Court to disturb a State’s decision
with respect to the definition of criminal conduct and the procedures by
which the criminal laws are to be enforced in the courts, including the bur-
den of producing evidence and allocating the burden of persuasion.”).
                          GRATZER v. MAHONEY                           1261
ments (and the facts undergirding them) do not include proof
that the defendant acted in the absence of mitigating circum-
stances.

   [6] Rather, Gratzer’s claims are akin to those discussed by
the United States Supreme Court in Patterson v. New York,
432 U.S. 197 (1977). In Patterson, the Court upheld the con-
stitutionality of a statute that required the defendant to prove
the affirmative defense of “extreme emotional disturbance”
by a preponderance of the evidence once the prosecution had
proved the elements of second degree murder beyond a rea-
sonable doubt. Id. at 206. So here, where Instruction No. 10A
stated that the prosecution was required to prove the two ele-
ments of Deliberate Homicide beyond a reasonable doubt; at
that point, imposing the burden on Gratzer to prove mitigation
(assuming this is, in fact, what the instruction did) was not
unconstitutional.
   [7] Gratzer next complains that the trial court’s failure to
assign the burden of proving mitigation to either party vio-
lated his right to due process and may have compromised the
jury’s unanimity task. It is true that Instruction No. 10A does
not allocate the burden of proving mitigation to either party;
this ambiguity left the jury in the admittedly unusual position
of speculating about who bore the burden. However, if it was
not constitutional error for the jury to place the burden of
proving mitigation on Gratzer (and Gratzer does not argue
that it would have been error for the jury to place the burden
of proving the absence of mitigation on the prosecution) then
Instruction No. 10A cannot violate the Constitution by failing
to assign the burden of proving mitigation.5 Gratzer fails to
make out a constitutionally colorable claim.
  5
    See Estelle v. McGuire, 502 U.S. 62, 72 (1991) (providing that the test
for an ambiguous jury instruction is “ ‘whether there is a reasonable likeli-
hood that the jury has applied the challenged instruction in a way’ that
violates the Constitution” (citing Boyde v. California, 494 U.S. 370, 380
(1990))
1262          GRATZER v. MAHONEY
  AFFIRMED.
