JUSTICE MULLARKEY delivered the Opinion of the Court.

The defendant, Jerome Walker (Walker), was convicted on October 2, 1992 in the Adams County District Court of second degree murder, section 18-3-103, 8B C.R.S. (1986). The court of appeals affirmed the conviction in an unpublished opinion, People v. Walker, No. 93CA0118 (Colo.App. Feb. 9, 1995), rejecting Walker's contention that the trial court's interpretation of the statutory scheme involving heat of passion and the prosecutor's comments during closing arguments impermissibly shifted the burden of proof of heat of passion to Walker in violation of due process of law. We granted certiorari to review the decision of the court of appeals, and we now affirm.

I.

On October 12, 1991, Walker and his friend, Hobart King (King), were drinking at Walker's home. Over the course of the day, arguments broke out between Walker and King, and, although the events leading up to the incident are disputed, Walker eventually fatally stabbed King with a knife.

On October 16, 1991, the People charged Walker with first degree murder. Walker entered a plea of not guilty, and the case went to trial on September 28, 1992.

At the close of the evidence, the jury was instructed on first degree murder, second degree murder, reckless manslaughter and heat of passion manslaughter. In addition, the jury was presented with instructions on the affirmative defenses of intoxication, defense of premises, and Walker's primary theory of self-defense. Walker tendered sample instructions and verdict forms which were rejected by the trial court. Walker's tendered instructions defined heat of passion manslaughter as a lesser included offense of first and second degree murder, requiring the prosecution to disprove the existence of heat of passion beyond a reasonable doubt in order to convict Walker of first or second degree murder. The instructions ultimately provided to the jury, however, followed the literal provisions of the statutory offense and defined heat of passion manslaughter as a lesser nonincluded offense for which the prosecution bore the burden of affirmatively proving, rather than disproving, the existence of heat of passion. The instruction read as follows:

In addition to determining the issues relating to the charge of First Degree Murder and the lesser included offenses of Second Degree Murder and Reckless Manslaughter, the jury shall determine whether the defendant, Jerome Walker, committed the lesser non-included offense of Heat of Passion Manslaughter. The defendant may be found guilty of a lesser non-included offense only if the evidence is sufficient to establish his guilt of the lesser non-included offense beyond a reasonable doubt.

. . . .

You should bear in mind that the burden is always upon the prosecution to prove beyond a reasonable doubt each and every material element of any lesser non-included offense; the law never imposes upon a defendant in a criminal case the burden of calling any witnesses or producing any evidence.

After considering all the evidence, if you decide the prosecution has proven each of the elements beyond a reasonable doubt, you should find the defendant guilty of Heat of Passion Manslaughter.

After considering all the evidence, if you decide the prosecution has failed to prove each of the elements beyond a reasonable doubt, you shoud [sic] find the defendant not guilty of Heat of Passion Manslaughter.

The court also provided a separate verdict form for the heat of passion manslaughter offense. Thus, the jury received two verdict forms: the first required the jury to return a verdict on first degree murder or one of the lesser included offenses of second degree murder or reckless manslaughter, and the second required the jury to consider separately Walker's innocence or guilt on the heat of passion manslaughter offense. The jury, therefore, was required to make a finding on the heat of passion manslaughter offense regardless of its decision on the other counts. During closing arguments, the prosecutor asserted several times that there was no evidence indicating heat of passion. On October 2, 1992, the jury returned a verdict of guilty of second degree murder and a verdict of not guilty of heat of passion manslaughter.

Walker contends that the effect of the trial court's interpretation of the statutory scheme and the prosecutor's closing comments was to impermissibly place the burden of proof of heat of passion on him in violation of due process of law.

The court of appeals affirmed the trial court's rulings and the judgment, holding that heat of passion manslaughter is a separate offense from murder, rather than a statutory mitigating factor of, or an affirmative defense to, second degree murder. In addition, the court of appeals found that the trial court had adequately described the prosecutor's burden of proof and that the prosecutor's comments did not constitute reversible error.

II.

To decide the case before us, we must first consider whether the trial court correctly interpreted the criminal provisions as written and then determine if such interpretation violated due process of law.

A.

Walker's primary argument is that the burden of proof of heat of passion manslaughter was placed on him in violation of due process of law. He contends that the trial court erroneously interpreted the statutory scheme in determining that heat of passion manslaughter is a lesser nonincluded offense rather than a factor in mitigation of, or affirmative defense to, second degree murder. In order to address this question, we begin with the criminal provisions at issue.

At the time of Walker's crime, heat of passion manslaughter was a class 4 felony defined as follows:

18-3-104. Manslaughter. (1) A person commits the crime of manslaughter if:

. . . .

(c) He knowingly causes the death of another person under circumstances where the act causing the death was performed upon a sudden heat of passion, caused by a serious and highly provoking act of the intended victim, affecting the person killing sufficiently to excite an irresistible passion in a reasonable person; but, if between the provocation and the killing there is an interval sufficient for the voice of reason and humanity to be heard, the killing is murder.

(2) Manslaughter is a class 4 felony.

§ 18-3-104, 8B C.R.S. (1986). At the same time, second degree murder was a class 2 felony under the following definition:

18-3-103. Murder in the second degree. (1) A person commits the crime of murder in the second degree if:

(a) He causes the death of a person knowingly, but not after deliberation.

§ 18-3-103, 8B C.R.S. (1986). Thus, under the law as it existed when the crime occurred, heat of passion manslaughter consisted of all the elements necessary to prove second degree murder plus additional elements involving heat of passion.

Walker concedes that the heat of passion manslaughter statute does not, on its face, shift the burden of proof of heat of passion to the defendant. Nonetheless, Walker argues that, under Mullaney v. Wilbur, 421 U.S. 684 (1975), the appropriate inquiry is whether the effect of the law as applied and enforced by the state shifts the burden of proof to the defendant in violation of due process of law.

Walker contends that because the jury was instructed that the prosecution bore the burden of proving, rather than disproving, the existence of heat of passion, Walker was denied the mitigating benefits of heat of passion. In particular, Walker reasons that, because heat of passion manslaughter as defined in the statute requires proof, in part, of all the elements of the more serious offense of second degree murder, the prosecution would have no incentive to charge or attempt to prove a heat of passion charge. Walker thus argues that a literal interpretation of the statute effectively requires a defendant to assume the burden of proof in order to receive the mitigating benefit of heat of passion. We disagree.

In Rowe v. People, 856 P.2d 486 (Colo. 1993), we considered the element of heat of passion as provided in an amended version of the statute defining first degree assault. In that case, the defendant had been convicted of an offense of first degree assault committed under heat of passion. Id. at 488. We were called upon to decide whether the General Assembly's amendment to the first degree assault statute provided the element of heat of passion as a statutory mitigating factor, a separate offense, or as an affirmative defense.

The amended first degree assault statute contained a provision stating that "[i]f assault in the first degree is committed under circumstances where the act causing the injury is performed . . . upon a sudden heat of passion . . . it is a class 5 felony[,] [but] [i]f [the] assault . . . is committed without [heat of passion] it is a class 3 felony." § 18-3-202, 8B C.R.S. (1986).

The prosecution requested and the trial court gave an instruction on the offense of first degree assault committed under heat of passion as a lesser included offense of first degree assault. Rowe, 856 P.2d at 488. We concluded, in agreement with the court of appeals, that heat of passion had been provided as a statutory mitigating factor, rather than a separate offense. Id. at 489. We noted that the element of heat of passion was contained in a subsection of the first degree assault statute that dealt exclusively with sentencing, rather than in the subsection which provided the elements defining the offense. Id. at 490. We also found that the General Assembly did not provide heat of passion as an affirmative defense, evidenced by the twin facts that heat of passion did not function to entirely negate a defendant's liability and the legislature did not label the element as an affirmative defense. Id. at 492. Thus, we concluded that

the General Assembly . . . includ[ed] heat of passion language in the statutory scheme for first-degree assault as a mitigating factor that could reduce a defendant's sentence for first-degree assault, rather than by creating a new and separate offense of first-degree assault committed under heat of passion or by establishing an affirmative defense.

Id. As support for this conclusion, we specifically highlighted the comparison between the criminal jury instructions on the element of heat of passion in the context of a charge of first degree assault and the criminal jury instructions on the element of heat of passion in the context of heat of passion manslaughter. Id. at 490.

Our analysis in Rowe is applicable to this case. Similar to the amended assault provisions discussed in Rowe, the homicide provisions at issue in this case do not define heat of passion as an affirmative defense, and heat of passion does not function to entirely negate a defendant's liability. In contrast to the provisions in Rowe, however, the homicide provisions at issue here do not define heat of passion as a statutory mitigating factor in sentencing. Rather, the statute defines heat of passion manslaughter as a separate offense for which the prosecution must prove each essential element. By the plain language of the criminal code in place at the time of the offense, the element of heat of passion in the homicide context was contained solely in the definition of heat of passion manslaughter, and the existence of heat of passion was necessary to prove the crime of heat of passion manslaughter. Thus, applying the Rowe analysis, we conclude that the trial court appropriately instructed the jury on the offense of heat of passion manslaughter as a separate offense.

The court of appeals has not been consistent in the determination of whether heat of passion manslaughter is an included or nonincluded lesser offense. However, we have stated that the offense is "technically not a lesser included offense of first- or second-degree murder." People v. Garcia, 826 P.2d 1259, 1262 (Colo. 1992) (citing People v. Lewis, 676 P.2d 682, 688 (Colo. 1984)). The court of appeals thus correctly determined that the offense was a lesser nonincluded offense.

Under section 18-1-408(5)(a), 8B C.R.S. (1986), an offense is considered an included offense of another when "[i]t is established by proof of the same or less than all the facts required to establish the commission of the offense charged." The criminal code in effect at the time of Walker's crime provided that heat of passion manslaughter was comprised of all the elements necessary to prove second degree murder and the additional elements of heat of passion. Thus, heat of passion manslaughter was not an included offense of second degree murder because it contained more, rather than less, elements than the offense of second degree murder. Therefore, the court of appeals did not commit error in affirming the trial court's presentation of heat of passion manslaughter as a lesser nonincluded offense.

Walker points out that for centuries heat of passion has been recognized as a mitigating factor in homicide, and that society has generally considered one who kills with provocation to be less culpable than one who kills without it. However, Walker erroneously concludes that because the trial court did not recognize heat of passion as a statutory mitigating factor, but rather found it to be a separate crime, Walker was denied the mitigating benefits of heat of passion. Contrary to Walker's assertions, the statute defining heat of passion manslaughter provides heat of passion as a mitigating factor in homicides. Under section 18-3-104, a homicide committed under heat of passion was defined as manslaughter and classified as a class 4 felony, while a homicide committed without heat of passion fell under section 18-3-103 and was defined as murder and a class 2 felony. Thus, under the statutory provisions in effect at the time of Walker's crime, a homicide committed in the heat of passion was considered and treated as less severe than a homicide committed without heat of passion. In other words, the provision of heat of passion manslaughter as a separate crime does not negate the mitigating effect of heat of passion, but merely provides it in a different form.

The trial court therefore correctly found that heat of passion manslaughter was a specific, lesser, nonincluded offense of second degree murder rather than a statutory mitigating factor. This conclusion was consistent with the plain language of the statute, as well as our cases interpreting the heat of passion manslaughter offense.

B.

Walker argues that such a literal interpretation of the heat of passion manslaughter offense impermissibly shifted the burden of proof of the element of heat of passion to him in violation of due process of law because the prosecution never would have an incentive to prove the existence of heat of passion. This is so, Walker argues, because proof of all the elements of second degree murder is a prerequisite to a finding of heat of passion manslaughter, and thus, whenever the prosecution could prove heat of passion manslaughter, it would have succeeded in proving second degree murder. While we acknowledge that the statute as written limits the occasions on which heat of passion manslaughter may be asserted, we disagree with Walker that the statute therefore violates due process of law.

In People v. Seigler, 832 P.2d 980 (Colo.App. 1991), the court of appeals rejected a defendant's argument that his due process rights were violated by the Colorado statutory scheme regarding heat of passion manslaughter because it required him to assume the burden of proof of the elements of heat of passion. In Seigler, the defendant was charged with one count of first degree murder and one count of crime of violence. Id. at 981. The jury was additionally instructed on the offense of second degree murder, all the manslaughter offenses, and the offense of criminally negligent homicide. Id. The defendant's primary argument was that his due process rights were violated because the court's instructions on heat of passion manslaughter as a lesser included offense of second degree murder, rather than as an affirmative defense to either first or second degree murder, impermissibly shifted the burden of proof of heat of passion to him. Id. at 983.

The defendant in Seigler acknowledged that the General Assembly had chosen to provide heat of passion as a separate offense for which the prosecution bore the burden to affirmatively prove the elements, rather than as an affirmative defense. He argued that because of this statutory scheme, the People rarely ever charged heat of passion manslaughter, and its disinterest in proving it effectively resulted in the defendant bearing the burden of proving the elements in order to gain the mitigating benefits. The court of appeals disagreed, and we find its reasoning persuasive.

The General Assembly determines the legal elements of crimes and delineates what circumstances will constitute excuse or justification. Seigler, 832 P.2d at 983 (citing People v. Carrier, 791 P.2d 1204 (Colo.App. 1990)). See also Patterson v. New York, 432 U.S. 197, 201-202 (1977) ("[I]t is normally `within the power of the State to regulate procedures under which laws are carried out, including the burden of persuasion,' and its decision in this regard is not subject to proscription under the Due process Clause unless `it offends some principle of justice so rooted in the traditions and conscience of our people as to be ranked as fundamental.'") (quoting Speiser v. Randall, 357 U.S. 513, 523 (1958)). Our task in construing a statute is to ascertain and to give effect to the intent of the General Assembly, not to second guess its judgment. Rowe v. People, 856 P.2d 486, 489 (Colo. 1993). In determining the intent of the General Assembly, we look first to the plain language of the statute. Id.; Goebel v. Colorado Dep't of Insts., 830 P.2d 1036, 1041 (Colo. 1992). Where the language is clear and unambiguous, we need not resort to rules of statutory construction. PDM Molding, Inc. v. Stanberg, 898 P.2d 542, 545 (Colo. 1995).

The statute at issue in this case is unambiguous. Section 18-3-104 provides for heat of passion as elements in the definition of manslaughter. It is true that, as the statute is written, heat of passion must be proved by the prosecution, so a defendant will receive the mitigating benefits of heat of passion only when it is proven. We do not agree with Walker, however, that this result is a violation of due process of law. There is no support for the contention that Walker has a constitutional right to the mitigating benefits of heat of passion, and we cannot say that, as the statute is written, the prosecution will not undertake the proof of heat of passion. Numerous circumstances exist in which a prosecutor might choose to charge or attempt to prove heat of passion manslaughter (e.g., when significant evidence of heat of passion exists, and the prosecution believes that a jury would not convict on second degree murder).

Walker relies, in large part, on the United States Supreme Court's decision in Mullaney v. Wilbur, 421 U.S. 684 (1975), to support his contention that the effect of the statute violates due process. In Mullaney, the Court struck down a Maine statute defining murder which contained a presumption of malice aforethought rebuttable by a defendant's proof of heat of passion. Id. The Court found that the presumption operated to place the burden of proof of an essential element of the offense on the defendant in violation of due process of law. Id. at 703-04. In reaching its conclusion, the Court explained that "the rationale of [In re Winship, 397 U.S. 358 (1970),] requires an analysis that looks to the `operation and effect of the law as applied and enforced by the state.'" Mullaney, 421 U.S. at 699 (quoting St. Louis S.W. R. Co. v. Arkansas, 235 U.S. 350, 362 (1914)). Walker argues that Mullaney, thus, requires us to look beyond the face of the statute to consider the effect of Colorado's heat of passion manslaughter offense as applied. Standing alone, Mullaney might compel the result Walker seeks.

However, two years later in Patterson v. New York, 432 U.S. 197 (1977), the Court limited the Mullaney holding by focusing on the formal presentation of the law. By so doing, the Court preserved broad discretion in state legislatures to define crimes. In Patterson, the United States Supreme Court held that due process does not require that the prosecution prove the nonexistence of all affirmative defenses. 432 U.S. at 210. The Patterson court found the Mullaney decision to be limited to requiring a state to prove beyond a reasonable doubt every essential element of an offense, thus prohibiting a state from presuming an essential element as Maine did in Mullaney. 432 U.S. at 215.

The Supreme Court in Patterson stated that "[t]he Due Process Clause, as we see it, does not put New York to the choice of abandoning [affirmative] defenses or undertaking to disprove their existence in order to convict of a crime which otherwise is within its constitutional powers to sanction by substantial punishment." 432 U.S. at 207-08. Likewise, the Due Process Clause does not require Colorado to provide an affirmative defense to be proven by the defendant or disproved by the prosecution in order to convict a defendant of a crime "which otherwise is within its constitutional powers to sanction by substantial punishment." Id. at 208.

Applying the Patterson rationale to the case before us, we find that the Colorado statutory scheme does not presume or imply any essential elements of the offenses of second degree murder or heat of passion manslaughter. The second degree murder statute does not contain any elements involving a presumption of the absence of heat of passion. In addition, the Colorado statutory definition of heat of passion manslaughter does require proof by the prosecutor of the presence of heat of passion. Thus, Colorado's statutory scheme does not shift the burden of proof of heat of passion to the defendant in violation of due process of law.

C.

Walker additionally argues that the prosecutor's comments during closing arguments served to shift the burden of proof to him. During the People's closing arguments, the prosecutor stated the following:

Then there's the lesser nonincluded offense. . . . [T]his is something you consider separately from [the other offenses]. . . . Knowingly, I've talked about that. Cause of death of another. Resulted in an act or act causing death performed under a sudden heat of passion, caused by a serious and highly provoking act. I submit to you right here, we have no serious and highly provoking act. Saying fuck you to somebody is not a serious, [sic] and there's no evidence. If you want to consider it, [the victim] saying I'm going to have sex with your daughter, there's no evidence he has a daughter. A serious and highly provoking act is, you know, you come home and maybe somebody is having sex with your five-year-old daughter. This is a highly and serious provoking act. We have nothing even approaching it.

Irresistible passion. This is completely inapplicable to any of the facts or evidence in this case and I would submit to you that it's not even worth — worth commenting on.

Later on rebuttal, the prosecutor additionally stated that

They want you to believe that this case is a provocation case, that this is provoking conduct on behalf of [the victim]. . . . This is not sufficient provoking conduct to amount to heat of passion manslaughter.

. . . .

Heat of passion manslaughter: if you believe that this was highly provoking conduct by [the victim] sufficient to excite an irresistible impulse in the person perceiving that conduct, that caused him to stab [the victim], then that should be your verdict. But read that element, it says if the opportunity for the voice of reason and humanity to be heard, if there's time for the opportunity or that there's an opportunity for the voice of reason to be heard, and it's not heat of passion, it's murder.

Walker contends that these comments shifted the burden of proof. We disagree.

In People v. Wadley, 890 P.2d 151 (Colo.App. 1994), a defendant challenged his conviction on the grounds that the prosecutor's closing comments at trial had served to shift the burden of proof of heat of passion to him. The prosecution argued during its closing remarks that the prosecution had failed to prove heat of passion beyond a reasonable doubt. Id. at 154. The prosecutor went on to specifically argue against heat of passion manslaughter on the grounds that there had been a sufficient time interval between the alleged provocation and the homicide in which to allow the defendant to heed the voice of reason. Id. Because the defendant had not objected to the prosecutor's comments contemporaneously, the court of appeals applied a plain error standard to the defendant's contention that the comments had impermissibly shifted the burden of proof of heat of passion to the defendant. Id. While the court indicated its disapproval of the prosecutor's statements, the court held that, given the context of the argument as a whole, and in light of the evidence presented at trial, the prosecutor's comments did not rise to the level of plain error. Id.

Similar to Wadley, in this case the defendant did not object contemporaneously that the prosecutor's closing argument shifted the burden of proof. Under such circumstances, the appropriate standard of review is plain error. Wilson v. People, 743 P.2d 415, 419 (Colo. 1987). Plain error occurs when "the error so undermined the fundamental fairness of the trial itself as to cast serious doubt on the reliability of the judgment of conviction." People v. Kruse, 839 P.2d 1, 3 (Colo. 1992). In addition, the evaluation of the propriety of counsel's argument involves consideration of the disputed statements in the context of the whole argument and in light of the evidence presented at trial. People v. Gutierrez, 622 P.2d 547, 554 (Colo. 1981).

The prosecutor's statements regarding heat of passion during closing argument in this case were less severe than the statements made in Wadley. In this case, the prosecutor stated that, in essence, there was no evidence of heat of passion. By contrast, in Wadley, the prosecutor explicitly stated that the prosecution had failed to prove the existence of heat of passion and affirmatively argued against the existence of one of the elements of the offense. 890 P.2d at 154. Nonetheless, the court of appeals held that the statements did not rise to the level of plain error. The court considered the argument as a whole, noting that the prosecutor mentioned during his closing remarks that the prosecution bore the burden of proof on all offenses, including heat of passion. Id. The court found that the prosecutor's argument as a whole did not contradict the instructions given to the jury. Therefore, the court concluded that the statements would not have led the jury to believe that the burden of proof of heat of passion was carried by the defendant. Id.

While the prosecutor's comments in this case asserted a lack of evidence of heat of passion, the instructions and verdict form provided to the jury regarding heat of passion manslaughter repeatedly emphasized that the prosecution bore the burden of proof of the elements of heat of passion as well as for all other essential elements of the offenses. In addition, the prosecutor indicated in his closing comments to the jury that the jury could "find the defendant guilty of [heat of passion manslaughter] as well as any one of the first, second, or reckless manslaughter." The prosecutor also reiterated on rebuttal that the People had "the burden of proof in this case." We conclude that the prosecutor's comments taken as a whole did not contradict the instructions given to the jury and would not have misled the jury to believe that Walker bore the burden of proof with regard to heat of passion.

III.