I concur in the majority’s holding, set forth in parts I and II of the majority opinion, that an unlawful intent to kill (what our law terms “express malice”) is an element of conspiracy to commit murder. The majority, however, does not reach the issue of whether conspiracy to commit murder is divided into degrees with differing punishments. Left unanswered, therefore, is this question: Is there conspiracy to commit first degree murder and conspiracy to commit second degree express-malice murder, or only conspiracy to commit murder? Unlike the majority, I would decide this issue, as it is likely to arise on remand and is of widespread significance to the law governing murder conspiracies, thus necessitating guidance to the bench and bar.
In deciding it, I would adhere to this court’s view in People v. Horn (1974) 12 Cal.3d 290 [115 Cal.Rptr. 516, 524 P.2d 1300] that conspiracy to commit first degree murder and conspiracy to commit second degree murder are separate crimes distinguished by whether the intent to kill reflected in the conspirators’ agreement is deliberate and premeditated or not. I would further conclude that under the Penal Code, each type of conspiracy to murder is subject to the punishment prescribed for the corresponding degree of murder.
I
As relevant here, defendants David Chatman and Jamal K. Swain were charged with murder and with conspiracy to commit murder. The trial court instructed the jury that murder required malice, that malice could be express or implied, and that conspiracy to commit murder required the specific intent to commit first or second degree murder. The instructions thus permitted the jury to find defendants guilty of conspiracy to commit second degree murder on an implied malice theory, that is, without finding they had the intent to kill. The jury convicted Chatman of second degree murder and conspiracy to commit second degree murder; it convicted Swain of conspiracy to commit second degree murder but acquitted him of murder. On the conspiracy conviction, the trial court sentenced each defendant to prison for 15 years to life, the punishment for second degree murder. Defendants appealed, contending that conspiracy to murder requires intent to kill as one of its elements; the People also appealed, contending that all conspiracies to murder were subject to a prison sentence of 25 years to life, the punishment for first degree murder. The Court of Appeal affirmed the judgments in their entirety.
II
I agree with the majority that conspiracy to murder requires proof of an unlawful intent to kill. I would, however, also decide the further question of *622whether there are separate crimes of conspiracy to commit first degree murder and of conspiracy to commit second degree express-malice murder, or whether conspiracy to commit murder is a unitary crime requiring only intent to kill. As I noted at the outset, the issue is a significant one affecting the jury instructions to be given in every murder conspiracy case and will inevitably arise if defendants are retried. As Justice Mosk notes in his concurring opinion, this court has in the past addressed issues likely to arise on remand of a case, and should do so here as well.
Penal Code section 182 (hereafter section 182) makes it unlawful for “(a) . . . two or more persons [to] conspire: [^Q (1) [t]o commit any crime” and establishes the punishment for conspiracies, including murder conspiracies. For crimes divided according to degree, section 182 provides for the following punishment: “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 to commit the felony 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." I shall refer to this as the punishment language of section 182.
The crime of murder is divided into degrees. At the time the murder at issue in this case occurred, Penal Code section 189 defined first degree murder as (1) “any . . . kind of willful, deliberate, and premeditated killing” (including killings accomplished by any of a variety of statutorily designated methods, the use of which in effect establishes deliberation and premeditation as a matter of law) or (2) murders “committed in the perpetration of, or attempt to perpetrate,” certain designated felonies (commonly referred to as felony murder). “All other kinds of murders are of the second degree." (Pen. Code, § 189.) First and second degree murder have different punishments. (Pen. Code, § 190.) Because murder is a crime “for which different punishments are prescribed for different degrees” (§ 182), the punishment language of section 182 on its face divides murder conspiracies into degrees, just as it does other crimes for which different punishments are prescribed for different degrees.
To understand the debate over whether the current version of section 182 divides conspiracy to murder into degrees, however, it is necessary to begin with People v. Kynette (1940) 15 Cal.2d 731 [104 P.2d 794] (hereafter Kynette), which was decided when a different version of section 182 was in effect. At that time, section 182 provided that a conspiracy was “punishable in the same manner and to the same extent as in this code provided for the *623punishment of the commission of the said felony.” (Former § 182, as amended by Stats. 1919, ch. 125, § 1, p. 170; Kynette, supra, 15 Cal.2d at p. 744.) The defendant in Kynette argued that the trial court improperly excluded jurors with reservations against the death penalty because, he contended, the death penalty (a possible penalty for first degree murder) was not a possible punishment for conspiracy to commit murder. (Id. at p. 744.) Thus, the issue was whether the penalty for first degree murder was a possible penalty for a conspiracy to commit murder.
In Kynette, this court held that the death penalty was a possible punishment for conspiracy to commit murder. (Kynette, supra, 15 Cal.2d at p. 745.) It reasoned that all conspiracies to commit murder were necessarily conspiracies to commit first degree murder. (Ibid.)
In 1955, 15 years after Kynette, supra, 15 Cal.2d 731, the Legislature changed the punishment language of section 182 to provide as follows: “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 to commit such felony 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.” (§ 182, as amended by Stats. 1955, ch. 660, § 1, p. 1155.) The punishment language of section 182 remains substantially the same today.
Almost 20 years after the Legislature altered section 182, this court addressed the effect of those changes on conspiracy to commit murder in People v. Horn, supra, 12 Cal.3d 290 (hereafter Horn). In that case, the court concluded that conspiracies to kill could take the form of conspiracies to commit first degree murder, conspiracies to commit second degree murder, and conspiracies to commit manslaughter. (Id. at pp. 298-300 & fn. 5.) In doing so, the court relied on three reasons: the existence of the diminished capacity defense; the then-existing requirement that for premeditation to exist the defendant must have “maturely and meaningfully reflect[ed] [on] the gravity of his contemplated act” (People v. Wolff (1964) 61 Cal.2d 795, 821 [40 Cal.Rptr. 271, 394 P.2d 959], italics omitted); and the post -Kynette changes to the punishment for murder conspiracies set forth in section 182. (Horn, supra, 12 Cal.3d at pp. 298-300 & fn. 5.) The court disapproved Kynette to the extent it was inconsistent. (Horn, supra, 12 Cal.3d at p. 301, fn. 8.)
As the majority notes, the first two reasons set forth in the Horn decision (supra, 12 Cal.3d 290) supporting the division of murder conspiracies into *624degrees—the existence of the diminished capacity defense and the “mature and meaningful reflection requirement”—are no longer the law. (Maj. opn., ante, at p. 608.) There remains, however, the punishment language of section 182.
The natural reading of the punishment language of section 182 makes conspiracies to murder punishable by degree, just as conspiracies to commit other crimes are punishable by degree. The first sentence of the punishment language of section 182 (“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.”) requires the trier of fact to ascertain the degree of the crime that is the object of the conspiracy, and thereby impliedly makes the punishment for the conspiracy the punishment for that degree of the crime. The second sentence of the punishment language of section 182 (“If the degree is not so determined, the punishment for conspiracy to commit the felony 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.”) states that when the degree is not determined, the punishment is to be for the lesser degree except in the case of murder, which is punished in the first degree. By its terms, the murder conspiracy exception just referred to is limited to cases in which the jury has not determined the degree; it is not an exception removing murder conspiracies entirely from classification and punishment by degree. Thus, Horn correctly concluded that, “[a]s this language is written and punctuated, it plainly authorizes the trier of fact to return a verdict finding conspiracy to commit murder in the second degree.” (Horn, supra, 12 Cal.3d at p. 298, fn. 5.) Nor is there any evidence of a contrary legislative intent underlying the enactment of section 182.
When this analysis of section 182 is coupled with our holding today that conspiracy to murder requires an unlawful intent to kill, the result is that a conspiracy to murder may be either a conspiracy to commit first degree murder or a conspiracy to commit second degree express-malice murder. The degree of the murder conspiracy depends on whether the conspirators’ agreement evidences a willful, deliberate, premeditated intent to kill of the type that distinguishes first degree murder or instead reflects only a bare intent to kill lacking in premeditation and deliberation.1 Reading section 182 as dividing conspiracy to murder into degrees, the punishment for each *625degree of conspiracy to commit murder is that for the underlying degree of murder. If the trier of fact fails to determine the degree, the conspiracy is subject to the punishment for first degree murder.
The reason for this structure of conspiracy to murder is readily apparent. If conspiracy to murder were a unitary crime that required only intent to kill, which is the mental state of second degree murder, but was punished as first degree murder, then conspiracies that involve agreements to commit only the elements of second degree murder (e.g., that lack premeditation and deliberation) would be punished more severely than the completed crime of second degree murder.
There is an additional reason for adhering to Horn’s conclusion that conspiracy to commit murder is divided by degrees. Horn has been the law for 21 years. During that time, the Legislature has not amended section 182 to change the understanding of murder conspiracy set forth in Horn. Therefore, the prudent and preferable course is to retain Horn’s structure of conspiracy to murder as a crime divided into degrees with different punishments for each degree. If the Legislature wishes to alter this structure of conspiracy to murder, it can do so. That significant policy decision, however, should be left to the Legislature.
Finally, I note that as a factual matter the crime of conspiracy to commit second degree express-malice murder applies only to a narrow range of cases—those in which conspirators formed an agreement to kill but made that agreement without deliberation and premeditation. It seems doubtful that any agreement persisting beyond more than the briefest duration would lack deliberation and premeditation, for inevitably the passage of time alone would cause the agreement to become deliberate and premeditated.
III
Justice Mosk, however, comes to a different conclusion than I have reached. He concludes that conspiracy to murder is a unitary crime that requires only intent to kill but is subject to the punishment for first degree murder. He therefore rejects this court’s view (Horn, supra, 12 Cal.3d 290) *626that the punishment language of section 182 recognizes the crime of conspiracy to commit second degree murder.
Although Justice Mosk relies on Kynette, supra, 15 Cal.2d 731, in reaching this conclusion, in my view Kynette does not really support his position. As the majority notes, proof of conspiracy requires proof that the conspirators intended to commit the elements of the offense that is the object of the conspiracy. (Maj. opn., ante, at p. 600.) In Kynette, this court stated 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.” (Kynette, supra, 15 Cal.2d at p. 745.) Kynette thus expresses the view that conspiracy to commit murder, as an agreement to commit the elements of first degree murder, requires proof that the conspirators’ intent to kill was deliberate and premeditated, but assumes that the agreement to murder itself will provide proof of deliberation and premeditation.
According to Justice Mosk, however, conspiracy to murder requires no mental state other than intent to kill. He states that “[t]he offense does not require, as a factual matter, a premeditated and deliberate intent to kill.” (Conc. opn. of Mosk, J., ante, at p. 613, italics in original.) In effect, Justice Mosk treats all conspiracies to commit murder as conspiracies to commit second degree express-malice murder—that is, the only mental state required, or relevant, to conspiracy to commit murder, in addition to intent to agree, is intent to kill, which is the mental state of second degree express-malice murder.2
For this reason, under Justice Mosk’s approach, every murder conspiracy would be punished as first degree murder even though the jury would have found only the mental state of second degree murder—intent to kill. Thus, conspiracy agreements to commit only the elements of second degree express-malice murder (e.g., agreements that lack premeditation and deliberation) and conspiracy agreements that reflect the premeditation and deliberation that distinguishes first degree murder would both be subject to the punishment established for first degree murder. As I have noted, this would produce the unjust and illogical result that second degree express-malice murder conspiracies would be punished more severely than the completed crime of second degree murder.
Furthermore, Justice Mosk’s position is contrary to the ordinary meaning of section 182. In justification, he suggests that to follow section 182’s plain *627language, under which murder conspiracies are subject to the punishment for first degree murder if the trier of fact fails to determine the degree of the murder that is the conspiracy’s object, would violate the general rule that when the trier of fact fails to determine the degree of the felony that is the object of a conspiracy, or the degree of a substantive felony, the defendant is only subject to the punishment prescribed for the lesser degree. (See Pen. Code, §§ 182, 1157, 1192.) There is, however, a logical reason why, when the trier of fact fails to determine the degree of the crime, murder conspiracies are punished in the first degree while conspiracies to commit all other crimes are punished in the lesser degree. Deliberate and premeditated murders are murders of the first degree. As Kynette recognized, in the typical murder conspiracy the conspirators will act with premeditation and deliberation in forming an agreement to commit the crime. (Kynette, supra, 15 Cal.2d at p. 745.) Punishing murder conspiracies of unspecified degree as first degree murder conspiracies simply accords with the statistical reality that the vast majority of murder conspiracies will involve premeditation and deliberation.
The deliberate and premeditated nature of most conspiracies, however, does not similarly increase the likelihood that conspiracies to commit crimes other than murder will be first degree conspiracies. Unlike murder, other crimes of degree do not become first degree by being premeditated and deliberate; as to those crimes, the degree of the crime typically turns on the nature of the defendant’s acts rather than the defendant’s mental state. For example, the degree of a robbery can vary depending on the location where the robbery occurs. (Pen. Code, § 212.5.) Thus, the fact that conspiracies to commit crimes other than murder may also reflect a premeditated and deliberate intent to commit the underlying crime does not support a similar “presumption” that the crime, if committed, would be in the first degree.
Justice Mosk also asserts that following the plain meaning of section 182 and recognizing the existence of both first and second degree murder conspiracies would mean that the Legislature, in enacting section 182 in 1955, intended to subject to the possibility of the death penalty anyone convicted of conspiracy to murder merely because the jury failed to specify the degree of the crime. His reading of section 182, however, under which all conspiracies to commit murder are punished the same as first degree murders and his view that conspiracy to commit murder is a unitary crime requiring only intent to kill leads to an even more extreme result, namely, that the Legislature intended to subject all murder conspirators to the death penalty even if they lacked the intent to commit the elements of first degree murder (e.g., premeditation and deliberation).
Finally, Justice Mosk notes that reading section 182 as dividing conspiracy to murder into degrees would mean that the Legislature implicitly *628rejected Kynette, supra, 15 Cal.2d 731, in adopting section 182. In my view, however, there is nothing so unreasonable about this conclusion that would justify this court, in order to avoid it, to depart from the ordinary meaning of the language used in that statute.
In my view, the post-Kynette, supra, 15 Cal.2d 731, punishment language of section 182, the decision in Horn, supra, 12 Cal.3d 290, and the Legislature’s acceptance of Horn foreclose the result that Justice Mosk proposes. Instead, I would continue to adhere to Horn's recognition that, under section 182, conspiracy to commit first degree murder (subject to the punishment prescribed for first degree murder) and conspiracy to commit second degree murder (subject to the punishment prescribed for second degree murder) are both possible crimes.
IV
I now turn to the question of the degree or degrees of conspiracy to murder for which these defendants may be retried, and what punishment they may receive if convicted. The scope of retrial and resentencing turns on the effect, if any, of two constitutional limitations: the prohibition against double jeopardy (Montana v. Hall (1987) 481 U.S. 400, 402 [95 L.Ed.2d 354, 358-359, 107 S.Ct. 1825]; People v. Santamaría (1994) 8 Cal.4th 903, 910-911 [35 Cal.Rptr.2d 624, 884 P.2d 81]) and the due process bar against retroactive increases in punishment (see People v. Escobar (1992) 3 Cal.4th 740, 752 [12 Cal.Rptr.2d 586, 837 P.2d 1100]; Bouie v. City of Columbia (1964) 378 U.S. 347, 352-354 [12 L.Ed.2d 894, 899-900, 84 S.Ct. 1697]).
In convicting defendants of conspiracy, the jury completed two verdict forms with respect to each defendant. First, it completed a form entitled “Verdict” and reading, “We, the jury in the above-entitled cause, find the defendant [name]_of the crime of felony, to wit: violation of Section 182.1 of the California Penal Code (Conspiracy)” by filling in the blank with the word “Guilty.” Second, it completed a form entitled “Finding on Object of Conspiracy” and reading, “We, the jury in the above-entitled cause, having found the defendant, [name] Guilty of conspiracy, find that defendant conspired to commit the crimes opposite the designation of which there has been placed an ‘X’.” There then follows a list of five crimes: first degree murder, second degree murder, voluntary manslaughter, involuntary manslaughter, and auto theft. The jury put an “X” next to second degree murder. Swain was also found not guilty of murder, voluntary manslaughter, and involuntary manslaughter (but guilty of intimidating a witness); Chat-man was also found guilty of second degree murder.
*629Defendant Swain, arguing that the only murder conspiracy crime existing now is conspiracy to commit first degree murder, contends that he cannot be retried because he was impliedly acquitted of conspiracy to commit first degree murder when the jury checked off only second degree murder as the object of the conspiracy. As I conclude that conspiracy to commit second degree express-malice murder is a possible crime, I reject this contention. Defendant Chatman, arguing that both first and second degree murder conspiracies are possible, apparently concedes that he can be retried for conspiracy to commit second degree murder but not conspiracy to commit first degree murder. The Attorney General, taking the position that the only crime at issue is conspiracy in the abstract, contends that the defendants were convicted of the only crime they were charged with (“conspiracy”) and were acquitted of nothing. The Attorney General contends that if their convictions are reversed, there are no limits on the crimes defendants can be charged with on retrial.
The Attorney General’s position lacks merit. It would for example, permit retrial not only of the full range of murder conspiracies that exist under the law (whether that is ultimately determined to be first and second degree murder, first degree murder, or simply “murder”) but also conspiracy to commit auto theft, one of the other options given to, but not chosen by, the jury that convicted defendants. Moreover, in Horn, supra, 12 Cal.3d at page 298, we rejected the view that conspiracy is a crime that exists in the abstract without reference to the crime that is the object of the conspiracy.
Rather, in accordance with my view that we should adhere to Horn’s, supra, 12 Cal.3d 290, division of conspiracy to murder into conspiracy to commit first degree murder and conspiracy to commit second degree express-malice murder, these defendants may be retried for conspiracy to commit second degree murder, the crime for which these defendants were convicted. Doing so will not violate the double jeopardy clause, for these defendants were convicted, not acquitted, of conspiracy to commit second degree murder, the crime for which they would be retried. (Montana v. Hall, supra, 481 U.S. at p. 402 [95 L.Ed.2d at pp. 358-359]; People v. Santamaria, supra, 8 Cal.4th at pp. 910-911.) If they are again convicted, there is no legal obstacle to the trial court again sentencing defendants to the punishment for second degree murder that they received before, as there would be no retroactive increase in the punishment to which they were previously subject. The protection against double jeopardy does preclude retrying these defendants for conspiracy to commit first degree murder, a crime of which *630they were impliedly acquitted. (See People v. Superior Court (Marks) (1991) 1 Cal.4th 56, 71, 74-76 [2 Cal.Rptr.2d 389, 820 P.2d 613]; Stone v. Superior Court (1982) 31 Cal.3d 503, 511 & fn. 5 [183 Cal.Rptr. 647, 646 P.2d 809].)
For purposes of this discussion, I include within the term “willful, deliberate and premeditated” the methods of killing designated in Penal Code section 189 that serve to elevate a killing to first degree murder. At the time of this case, those methods were killing “by means of a destructive device or explosive, knowing use of ammunition designed primarily to *625penetrate metal or armor, poison, lying in wait, [or] torture.” (Ibid.) Moreover, as a practical matter, a conspiracy to kill by one of these methods almost inevitably will involve deliberation and premeditation. Because it is not at issue in this case, I do not address whether conspiracy to commit first degree murder is a possible crime in cases in which the first degree murder theory would be felony murder, rather than deliberation and premeditation. Presumably, if it is possible for a defendant to be convicted of conspiracy to commit first degree murder on a felony-murder theory, under today’s holding the prosecution would have to prove intent to kill, even though it is not an element of first degree felony murder.
In his dissent in Horn, supra, 12 Cal.3d 290, 304, however, Justice Mosk did recognize conspiracy to commit second degree murder as a separate crime in “those instances when the planned method of killing falls within the Penal Code section 189 definition of murder in the second degree.” (Ibid. (dis. opn. of Mosk, J.).)