Petitioner Thomas Charles Kleve appeals pro se from the district court’s denial of his habeas petition under 28 U.S.C. § 2254. The central issue on appeal is whether petitioner was convicted of a non-existent crime when he was convicted in 1989 of conspiracy to commit second degree murder in violation of California Penal Code § 182. We have jurisdiction under 28 U.S.C. § 2253. We hold that petitioner’s conviction was valid, and we affirm.
I.
BACKGROUND
On September 29, 1987, a Los Angeles County Sheriffs Department Deputy stopped petitioner’s truck because it had an expired registration tag. As petitioner got out of the driver’s side of the truck, the deputy saw that his passenger, Clinton Calley, had a street map open in his lap and a shotgun partially hidden in his jacket. A search of the truck revealed a case containing a dagger, a semi-automatic 9-millimeter pistol and two magazines containing live rounds that fit the pistol. A pat-down search of petitioner revealed additional 9-millimeter live rounds. A pat-down search of Calley revealed an explosive device in his jacket pocket. During a post-arrest booking search, officers found a note in Calley’s wallet with the name Mark Hallin, a physical description of Hal-lin, two non-existent addresses on Ram-hurst Street (where Hallin lived, but at a different address), a description of Hallin’s car and motorcycle, and the date September 29, 1987. The Sheriffs Department determined that the explosive device found in Calley’s pocket could have been attached to the starter of Hallin’s motorcycle and detonated when the motorcycle was started.
The Los Angeles District Attorney charged petitioner with conspiracy to commit first degree murder; transporting a destructive device; possession of a silencer; carrying a loaded firearm; and permitting a loaded firearm in a vehicle. At petitioner’s first trial, a jury found him not guilty of possession of a silencer, but guilty of two misdemeanor counts of carrying a loaded firearm and two misdemeanor counts of permitting a loaded firearm in a vehicle. The jury was unable to reach a verdict on the remaining charges. Following retrial, a second jury found petitioner not guilty of conspiracy to commit first degree murder, but guilty of conspiracy to commit second degree murder in violation of California Penal Code § 182.2
Petitioner unsuccessfully challenged his conviction on direct appeal and in several state habeas petitions. Following dismissal of prior federal habeas petitions for failure to exhaust, petitioner filed this petition in 1996. The district court denied the *1011petition. This appeal followed. We review de novo the district court’s denial. See Eslaminia v. White, 136 F.3d 1234, 1236 (9th Cir.1998).
II.
DISCUSSION
A. Petitioner’s Claim that He Was Convicted of a Non-existent Crime
At the time of petitioner’s conviction in 1989, California Penal Code § 182 provided that when two people conspire to commit a felony
they shall be punishable in the same manner and to the same extent as is provided for the punishment of that felony. If the felony is one for which different punishments are prescribed for different degrees, the jury or court tohich finds the defendant guilty thereof shall determine the degree of the felony defendant conspired to commit. If the degree is not so determined, the punishment for conspiracy shall be that prescribed for the lesser degree, except in the case of conspiracy to commit murder, in ivhich case the punishment shall be that prescribed for murder in the first degree.
Cal.Penal Code § 182 (italics indicate language added in 1955). The California Supreme Court held last year, in People v. Cortez, 18 Cal.4th 1223, 77 Cal.Rptr.2d 733, 960 P.2d 537 (1998), that there is no crime of conspiracy to commit second degree murder under California law: “[A]ll conspiracy to commit murder is necessarily conspiracy to commit premeditated and deliberated first degree murder, and ... all murder conspiracies are punishable in the same manner as murder in the first degree pursuant to the punishment provisions of Penal Code section 182.” Id. at 1237-38, 77 Cal.Rptr.2d 733, 960 P.2d 537. Relying on Cortez, petitioner contends that conspiracy to commit second degree murder was not a crime under California law at the time of his conviction.
There are two possible responses to petitioner’s contention. First, we could conclude that California law has evolved since the time of petitioner’s conviction. Under this conclusion, the California Supreme Court’s decision in Cortez states the law new, but it does not accurately describe the law when petitioner was convicted. In that event, petitioner’s case is relatively straightforward. California is free to change its criminal law prospectively without undermining the validity of convictions obtained under the old law. See Pulley v. Harris, 465 U.S. 37, 42, 104 S.Ct. 871, 79 L.Ed.2d 29 (1984) (holding a claim based on evolution of state law is a matter of state law properly addressed to the state courts); Wainwright v. Stone, 414 U.S. 21, 23-24, 94 S.Ct. 190, 38 L.Ed.2d 179 (1973) (holding Florida not constitutionally compelled to make a new construction of criminal statute retroactive); La Rue v. McCarthy, 833 F.2d 140, 142-43 (9th Cir.1987) (finding no due process violation where the California Supreme Court changed the felony-murder rule after petitioner’s conviction became final); see also Fiore v. White, 149 F.3d 221, 224-26, n. 4 (3d Cir.1998) (holding state courts not required to apply new statutory interpretation retroactively even where new interpretation was announced in a co-defendant’s case), cert. granted, - U.S. -, 119 S.Ct. 1332, 143 L.Ed.2d 497 (1999). Thus, if Cortez is an evolution of California law, petitioner cannot successfully attack his conviction based on an argument that conspiracy to commit second degree murder was not a crime when he was convicted.
Second, we could conclude that California law has not evolved and that the law stated by the California Supreme Court in Cortez in 1998 was also the law in 1989. Although the matter is not free from doubt, there is some basis for that conclusion. We know that conspiracy to commit second degree murder was not a crime in California in 1940. See People v. Kynette, 15 Cal.2d 731, 744, 104 P.2d 794 (1940), overruled on other grounds, People v. Snyder, 50 Cal.2d 190, 197, 324 P.2d 1 (1958). *1012In 1940, the relevant punishment language of § 182 provided:
When [two or more persons] conspire to commit any felony ... they shall be punishable in the same manner and to the same extent as in this code provided for the punishment of the commission of the said felony[.]
Cal.Penal Code § 182, as amended by Stats. 1919, ch. 125, § 1, p. 170. Interpreting that language, the California Supreme Court in Kynette held that
a conspiracy to commit murder can only be a conspiracy to commit murder of the first degree for the obvious reason that the agreement to murder necessarily involves the ‘willful, deliberate, and premeditated’ intention to kill a human being.
15 Cal.2d at 745, 104 P.2d 794.
In 1955, the California legislature added two sentences to the punishment language of § 182. Those sentences, which remain in the statute today, provide:
If the felony is one for which different punishments are prescribed for different degrees, the jury or court which finds the defendant guilty thereof shall determine the degree of the felony defendant conspired to commit. If the degree is not so determined, the punishment for conspiracy shall be that prescribed for the lesser degree, except in the case of conspiracy to commit murder, in which case the punishment shall be that prescribed for murder in the first degree.
Cal.Penal Code § 182, as amended by Stats.1955, ch. 660, § 1, p. 1155. Nearly twenty years later, the California Supreme Court in dictum interpreted the added language as establishing the crime of conspiracy to commit second degree murder. See People v. Horn, 12 Cal.3d 290, 115 Cal.Rptr. 516, 524 P.2d 1300 (1974). In a footnote, the Horn Court stated:
Kynette’s assertion that a conspiracy to commit murder is always a conspiracy to commit first degree murder is inconsistent with the present language of Penal Code section 182.... As [the] language [of § 182] is written and punctuated, it plainly authorizes the trier of fact to return a verdict finding conspiracy to commit murder in the second degree. Only if the trier of fact fails to determine the degree is a conspiracy to commit murder punished as one to commit first degree murder. Since the Legislature has authorized a verdict of conspiracy to commit second degree murder, it clearly does not believe that crime to be a logical impossibility.
12 Cal.3d at 298, n.5, 115 Cal.Rptr. 516, 524 P.2d 1300.
The California Supreme Court did not interpret the two new sentences of § 182 again until its recent decisions in People v. Swain, 12 Cal.4th 593, 49 Cal.Rptr.2d 390, 909 P.2d 994 (1996), and, two years later, in Cortez. In Swain, the Court hinted that there was no crime of conspiracy to commit second degree murder, but the Horn dictum was not explicitly repudiated until Cortez. The Court in Cortez concluded that the two sentences added to § 182 in 1955
[were] not intended to authorize the substantive offense of conspiracy to commit second degree express malice murder, and [were] intended instead to codify [the] holding in Kynette by acknowledging that all murder conspiracies are the functional equivalent of conspiracy to commit premeditated first degree murder[.]
18 Cal.4th at 1236 n.5, 77 Cal.Rptr.2d 733, 960 P.2d 537. The Court in Cortez did not specify whether its interpretation of § 182 is to be applied retroactively. For purposes of the analysis that follows, we assume that Cortez is retroactive and that conspiracy to commit second degree murder was not a crime at the time of petitioner’s conviction.
All murder under California law requires “malice aforethought,” which includes an “intent to kill.” First degree murder requires premeditation and deliberation, while second degree murder is characterized by the absence of premeditation and deliberation. Under Cortez, any *1013conspiracy to commit murder is treated as if it were a conspiracy to commit first degree murder. According to Cortez, conspiracy is a “specific intent” crime requiring both “an intent to agree or conspire and a further intent to commit the target crime or object of the conspiracy.” Id. at 1232, 77 Cal.Rptr.2d 733, 960 P.2d 537. Even though the “target crime” in Cortez was murder, the jury in that case was never instructed that it needed to find premeditation and deliberation in order to convict. The Court in Cortez held that so long as the jury found specific intent to conspire to commit murder, the mental state necessary for conspiracy was sufficient to justify treating any conspiracy to commit murder as the equivalent of conspiracy to commit first degree murder. The Court explained:
[I]t logically follows that where two or more persons conspire to commit murder-i.e., intend to agree to conspire, further intend to commit the target offense of murder, and perform one or more overt acts in furtherance of the planned murder-each has acted with a state of mind “functionally indistinguishable from the mental state of premeditating the target offense of murder.” The mental state required for conviction of conspiracy to commit murder necessarily establishes premeditation and deliberation of the target offense of murder-hence all murder conspiracies are conspiracies to commit first degree murder, so to speak. More accurately stated, conspiracy to commit murder is a unitary offense punishable in every instance in the same manner as is first degree murder under the provision of Penal Code section 182.
Id. at 1232, 77 Cal.Rptr.2d 733, 960 P.2d 537 (citations omitted).
We believe that the most plausible interpretation of Cortez, as applied to petitioner’s case, is that petitioner was validly convicted of conspiracy to commit murder under California law but was punished more leniently than Cortez contemplates. In convicting petitioner of conspiracy to commit second degree murder, the jury found that petitioner (1) intended to agree to commit murder, and (2) had the required mental state-malice aforethought-to commit the target crime of murder. Under Cortez, this is all that is required for a conviction for conspiracy to commit murder under California law. Thus, because the jury found that petitioner had conspired to commit murder, his conspiracy was the equivalent under Cortez of conspiracy to commit first degree murder and was punishable as if he had committed first degree murder. In fact, however, petitioner was punished not as if he had committed first degree murder, but rather as if he had committed second degree murder. Thus, under Cortez, there was an error in petitioner’s sentencing, but the error worked for rather than against petitioner.
Petitioner could argue that his acquittal on the charge of conspiracy to commit first degree murder is inconsistent with a conviction for what, under Cortez, is the only crime for which he could have been convicted-the unitary crime of conspiracy to commit murder. It is true that petitioner’s acquittal necessarily means that the jury found he did not premeditate and deliberate with respect to the target crime of murder. This does not mean, however, that petitioner could not be convicted of what, under Cortez, is treated as conspiracy to commit first degree murder. This is so for either of two reasons.
First, we may understand the acquittal on the more serious charge and the conviction on the less serious charge simply as inconsistent verdicts. United States v. Powell, 469 U.S. 57, 64-68, 105 S.Ct. 471, 83 L.Ed.2d 461 (1984), holds that an inconsistent verdict is not invalid; it is simply inconsistent. Second, and alternatively, we may understand the two verdicts as consistent. Though the opinion is not free from ambiguity, Cortez can be read to hold not that all conspiracy to commit murder is, in fact, conspiracy to commit first degree murder, but rather that it may be treated for purposes of punishment as the *1014equivalent of conspiracy to commit first degree murder. Under this reading of Cortez, the jury’s acquittal on the charge of conspiracy to commit first degree murder-i.e., its finding that petitioner did not conspire to murder with premeditation and deliberation of that murder-is neither here nor there. That is, under this reading, petitioner’s crime was not actual conspiracy to commit first degree murder, but rather its functional equivalent. In the words of the California Supreme Court, it was conspiracy to commit first degree murder, “so to speak.” Cortez, 18 Cal.4th at 1232, 77 Cal.Rptr.2d 733, 960 P.2d 537.
We therefore conclude that, even if Cortez states the law of California as it has been since the Kynette decision in 1940, petitioner was convicted of a crime under California law. The court in 1989 called petitioner’s crime conspiracy to commit second degree murder, even though Cortez tells us today that his crime was conspiracy to commit first degree murder or its equivalent. The court in 1989 also punished petitioner’s crime as if it had been a conviction for second degree murder, even though Cortez tells us today that it should have been punished as a conviction for first degree murder. But we do not believe that mislabeling petitioner’s crime and punishing him with undeserved leniency provide a basis for invalidating his conviction altogether.
B. Petitioner’s Other Claims
Petitioner has raised a number of additional claims, none of which depend on his argument under Cortez that he was convicted of a non-existent crime. In a separate unpublished memorandum, we affirm the district court’s decision denying these claims.
For the foregoing reasons, the district court’s denial of the petition is AFFIRMED.
. Clinton Calley was convicted by the same jury of conspiracy to commit first degree murder, possession of a destructive device, and transportation of a destructive device.