OPINION OF THE COURT
ALDISERT, Circuit Judge.This court is required to resolve a knotty Fourteenth Amendment problem in Pennsylvania murder trials which has evenly divided the justices on that state’s highest court.1 We are to decide whether, in a prosecution on a murder indictment, the Fourteenth Amendment requires the trial court, upon request, to give the jury the option of returning a verdict of voluntary manslaughter.2 Adopting a Magistrate’s Report and Recommendation, the district court reasoned that because Pennsylvania case law permits a jury verdict of voluntary manslaughter in the absence of evidence supporting the elements of that offense,3 and also permits the trial court to exercise its discretion in deciding whether to give instructions on voluntary manslaughter,4 a failure to submit the issue to the jury violated the defendant’s constitutional rights of Due Process and Equal Protection. Accordingly, it granted a writ of habeas corpus. The Commonwealth appealed. Without reaching the Equal Protection issue, we affirm.
The relevant facts were summarized briefly in Commonwealth v. Matthews, 446 Pa. 65, 285 A.2d 510, 511 (1971):
From the evidence, the jury was warranted in finding that Matthews, on February 23, 1968, acting in concert with his nephew, James Williams, and a friend, James Jackson, robbed Randolph Butts in Philadelphia and during the perpetration of the robbery Butts was stabbed four times by one of the felons, causing injury which resulted in Butts’ death.
*341I.
We begin our analysis with the Pennsylvania substantive law of voluntary manslaughter. For federal purposes we accept Justice Pomeroy’s statement of the appropriate state law:
While it is considered felonious, voluntary manslaughter is the least culpable form of homicide included with a murder indictment. Thus, when considering the degree of culpability of an individual being tried under such an indictment, a jury may return a voluntary manslaughter verdict if it finds that the killing, although intentional, was committed without malice; that is, the accused may be shown to have been acting under the influence of sudden passion which was caused by legally adequate provocation that placed him beyond the control of reason.[5] See e. g., Commonwealth v. Walters, 431 Pa. 74, 244 A.2d 757 (1968); Commonwealth v. Paese, 220 Pa. 371, 69 A. 891 (1908). These elements need not always be present, however, to support a voluntary manslaughter verdict. Pennsylvania courts have long accepted the common law rule that the jury has the power to find a defendant guilty of voluntary manslaughter even in the absence of passion or provocation, where the evidence is sufficient to support a first or second degree murder verdict. Commonwealth v. Hoffman, 439 Pa. 348, 266 A.2d 726 (1970); Commonwealth v. Kellyon, 278 Pa. 59, 122 A. 166 (1923); Commonwealth v. Gable, 7 Serg. & R. 423 (1821). Although superficially such a rule may seem incongruous, it does have a rational basis. In essence, the rationale of the rule is founded on two considerations: (1) the legal concept that voluntary manslaughter is by definition a lesser offense than murder but one included within a murder indictment, (2) a realistic appreciation of the fact that factors such as sympathy or extenuating .circumstances may lead a jury to find a defendant guilty of the lesser included offense of voluntary manslaughter even though the evidence is enough to establish guilt of murder in the second or even the first degree. Commonwealth v. Hoffman, supra.
Imposed upon this conceptual framework is a second rule. . That rule gives a trial judge complete discretion in deciding whether or not to submit voluntary manslaughter to the jury as a possible verdict in a case where there is no evidence of passion or provocation.[6] See, e. g., Commonwealth v. LaRue, 381 Pa. 113, 112 A.2d 362 (1955); Commonwealth v. Yeager, 329 Pa. 81, *342196 A. 827 (1938). The reason for this rule is said to be that a charge on a point or issue which is unsupported by any evidence “ . . .is likely to confuse the jury and obstruct Justice.” Commonwealth v. Pavillard, 421 Pa. 571, 220 A.2d 807 (1966).
Commonwealth v. Matthews, supra, 285 A.2d at 517.
II.
The genesis of the federal constitutional problem is the anomaly that although the jury has unfettered power to return a voluntary manslaughter verdict as a lesser included offense of a murder indictment, it could not do so if the trial judge refused to charge on this point. Thus, whether the jury was given this opportunity was solely dependent upon the unrestricted discretion of the trial judge.7 Justice Pomeroy, speaking for himself and Justice Roberts, concluded:
In my view, the due process and equal protection clauses of the Fourteenth Amendment require the abandonment of the procedure now again sanctioned by the court. Due process is violated where a state procedure denies to those subject to it the fundamental fairness required in a system of ordered liberty. Rochin v. California, 342 U.S. 165, 169, 72 S.Ct. 205, 96 L.Ed. 183 (1952). The procedure here, grounded as it is upon the exercise of absolute discretion by the trial judge, without the benefit of any objective standards to guide him, is patently arbitrary and unfair.
Commonwealth v. Matthews, supra, 285 A.2d at 518.8
The majority in Matthews did not meet the constitutional issue:
Appellant next asserts the trial court committed error in refusing a specific request to instruct the jury on voluntary manslaughter, and also in failing to submit to the jury such a finding as a possible verdict. Since there was no evidence which pointed in the slightest degree to the offense of manslaughter, the court’s action did not constitute error. Commonwealth v. LaRue, 381 Pa. 113, 112 A.2d 362 (1955); and Commonwealth v. Flax, 331 Pa. 145, 200 A. 632 (1938).
285 A.2d at 514.9
*343III.
Thus, to offset Justice Pomeroy’s constitutional contentions we must turn to the argument presented by the Commonwealth. It builds first on Sparf v. United States, 156 U.S. 51, 15 S.Ct. 273, 39 L.Ed. 343 (1895), which approved a jury charge given in a trial for murder on the high seas, which charge instructed the jury that it was not authorized to return a verdict of manslaughter because there was no evidence showing that crime. The Court stated: “A verdict of guilty of an offense less than the one charged would have been in flagrant disregard of all the proof, and in violation by the jury of their obligation to render a true verdict. There was an entire absence of evidence upon which to rest a verdict of guilty of manslaughter or simple assault. A verdict of that kind would have been the exercise by the jury of the power to commute the punishment for an offense actually committed, and thus impose a punishment different from that prescribed by law.” Id. at 64, 15 S.Ct. at 278. Moreover, the Commonwealth directs us to Government of the Virgin Islands v. Carmona, 422 F.2d 95, 101 (3d Cir. 1970), in which we held “there was no error in failing to charge as to voluntary manslaughter in the circumstances of the instant ease. As there was no evidence of a quarrel or fit of passion, the jury could not have correctly found Carmona guilty of voluntary manslaughter,” citing Stevenson v. United States, 162 U.S. 313, 315, 16 S.Ct. 839, 40 L.Ed. 980 (1896).
Next, the Commonwealth argues that notwithstanding these and other cases, courts have found it necessary to uphold a defendant’s conviction of a lesser included offense where a trial judge erroneously submitted the offense to the jury. The underlying rationale of these latter cases is that the Constitutional prohibition against double jeopardy10 barred correction of the trial judge’s error.
But neither Sparf nor Carmona meets the Due Process argument properly presented in these federal habeas corpus proceedings. The Supreme Court in Sparf and this court in Carmona were confronted with issues of statutory construction only;11 neither discussed the Pennsylvania practice presently under review.12
The Commonwealth then emphasizes that “[n]o court has held that because jury instructions not recognized by the law and overly favorable to one defendant were given at his trial, that thereafter every defendant is entitled to those same instructions.”13 Underlying this argument is the assumption that, in Pennsylvania, the jury could not properly return a verdict of voluntary manslaughter on a murder indictment absent evidence of passion or provoca*344tion. However the common law14 and Pennsylvania substantive law recognize the jury’s “power,”15 indeed “prerogative,” 16 to return such a verdict if the court submits the issue to them. Moreover, in upholding such verdicts, the Pennsylvania Supreme Court has not relied on double jeopardy grounds but on the twofold consideration stated recently in Commonwealth v. Hoffman, supra, 266 A.2d at 732: “a realistic appreciation of the humanity of those who sit on our juries, and the legal concept that voluntary manslaughter is by definition a lesser [included] offense than murder but one included in a murder indictment.”
Our research has not disclosed a Pennsylvania Supreme Court decision which unequivocally held that, on an indictment for murder, it would be error for a trial judge to charge on voluntary manslaughter where there was no evidence of passion or provocation. The court has had numerous opportunities to do so 17 but instead has framed its holding in terms of what a defendant has a right to expect or whether the trial court’s refusal to instruct was in error. These cases still leave the final decision on whether to charge within the discretion of the trial judge. We now proceed to a consideration of the Due Process argument.
IV.
At a time when the contours of procedural due process were beginning to become visible, Mr. Justice Cardozo recognized the difficulty in establishing a universal definition of due process: “The line of division may seem to be wavering and broken if there is a hasty catalogue of the cases on the one side and the other. Reflection and analysis will induce a different view. There emerges the perception of a rationalizing principle which gives to discrete instances a proper order and coherence. * * * Does it violate those ‘fundamental principles of liberty and justice which lie at the base of all our civil and political institutions’?" Palko v. Connecticut, 302 U.S. 319, 325, 328, 58 S.Ct. 149, 152, 82 L.Ed. 288 (1937) (citations omitted).18 Later Mr. Justice Frankfurter would emphasize that “[r]egard for the requirements of the Due Process Clause ‘inescapably imposes upon this Court an exercise of judgment upon the whole course of the proceedings [resulting in a conviction] in order to ascertain whether they offend those canons of decency and fairness which express the notions of justice of English-speaking peoples even toward those charged with the most heinous offenses.’ ” Ro-chin v. California, 342 U.S. 165, 169, 72 S.Ct. 205, 208, 96 L.Ed. 183 (1952) (citation omitted).
In the decades which have followed, the Supreme Court has not formulated a bright line definition. But, in discussing the right to a jury trial in a criminal case, the Court expressed this country’s historic desire to minimize arbi*345trary judicial activity: “The framers of the Constitution strove to create an independent judiciary but insisted upon further protection against arbitrary action. Providing an accused with the right to be tried by a jury of his peers gave him an inestimable safeguard against the corrupt or overzealous prosecutor and against the complaint, biased, or eccentric judge. * * * Beyond this, the jury trial provisions in the Federal and State Constitutions reflect a fundamental decision about the exercise of official power — a reluctance to entrust plenary powers over the life and liberty of the citizen to one judge or to a group of judges.” Duncan v. Louisiana, 391 U.S. 145, 156, 88 S.Ct. 1444, 1451, 20 L.Ed.2d 491 (1968) (emphasis supplied).
To recite these broad-base principles is to reinforce the conclusion reached by Pennsylvania Justices Roberts, Pomeroy and Manderino in Commonwealth v. Jones, supra, that the Pennsylvania practice did 'not comport with the protections extended this appellee by the Constitution. At the time he was tried, the jury was given the option of returning a verdict of murder in the first degree calling for life imprisonment or death,19 or alternatively, a verdict of murder in the second degree, calling for a sentence of up to twenty years. Another trial judge, or the same judge on another day, could have permitted the jury to return a verdict of voluntary manslaughter, calling for a sentence of no more than twelve years. To deny ap-pellee the possibility of a lesser verdict with a lesser restraint of liberty is permissible only if the denial comports with due process. To deny appellee the possibility of a lesser restraint of liberty because of a practice which permits arbitrary trial court activity is offensive to those settled concepts of due process.
The opinion in support of affirmance 20 in Commonwealth v. Davis, supra, 297 A.2d at 821, essentially acknowledged the absence of standards prior to May 2, 1974: “[T]he establishment of objective standards for application in all cases must await further development of our case law. . : .” A lack of any standard to guide a decision which has the capability of restricting the liberty or property of a defendant would seem to offend settled concepts of due process. Thus, in invalidating a Pennsylvania practice which failed to furnish a criminal court jury with standards to guide a decision as to whether costs should be imposed upon a defendant in whose favor a not guilty verdict was rendered, the Supreme Court found the practice “vague and standardless,” and therefore offensive to due process:
It is established that a.law fails to meet the requirements of the Due Process Clause if it is so vague and standardless that it leaves the public uncertain as to the conduct it prohibits or leaves judges and jurors free to decide, without any legally fixed standards, what is prohibited and what is not in each particular case. See e.g., Lanzetta v. New Jersey, 306 U.S. 451 [59 S.Ct. 618, 83 L.Ed. 888]; Baggett v. Bullitt, 377 U.S. 360 [, 84 S.Ct. 1316, 12 L.Ed.2d 377], This 1860 Pennsylvania Act contains no standards at all, nor does it place any conditions of any kind upon the jury’s power to impose costs upon a defendant who has been found by the jury to be not guilty of the crime charged against him. * * * Certainly one of the basic purposes of the Due Process Clause has always been to protect a person against having the Govern*346ment impose burdens upon him except in accordance with the valid laws of the land. Implicit in this constitutional safeguard is the premise that the law must be one that carries an understandable meaning with legal standards that courts must enforce. This state Act as written does not even begin to meet this constitutional requirement.
Giaccio v. Pennsylvania, 382 U.S. 399, 402-403, 86 S.Ct. 518, 520, 15 L.Ed.2d 447 (1966).
It is undisputed that there are no “legal standards that courts must enforce” in giving or not giving the manslaughter charge in a Pennsylvania murder indictment. Accordingly, we conclude that the powerful rationale of Giaccio commands a similar result in this case.
We believe that the safeguards of due process will be satisfied only when all defendants in Pennsylvania murder trials are given the same opportunity, upon request duly made, to have a jury return a verdict of voluntary manslaughter as well as first and second degree murder.21 To hold otherwise is to expose a defendant to the idiosyneracies of the trial judge to whom the case has been assigned, or the “whim or caprice” 22 of a given judge on a given day. Accordingly, we affirm the judgment of the district court.22a
V.
The Commonwealth advances the argument that “[i]f this Court should conclude that a valid constitutional issue is presented, it would be inappropriate to reverse Matthews’ conviction.” (Commonwealth brief at 6 n.l.) It reasons that this defendant has suffered no prejudice because the jury in fact returned a verdict of first degree and not second degree murder. Thus, the Commonwealth argues harmless error. This contention overlooks the possibility that if a jury had three options instead of two, the jury could have compromised on the middle ground of second degree. Although of course no one can say with precision that given three alternatives, the jury has a greater probability of compromise, we do recognize that with three alternatives, at least “there is a reasonable possibility” of compromise. Schneble v. Florida, 405 U.S. 427, 432, 92 S.Ct. 1056, 31 L.Ed.2d 340 (1972).23 Therefore, we cannot say that failure to give the charge “was harmless beyond a reasonable doubt.” Chapman v. California, 386 U.S. 18, 24, 87 S.Ct. 824, 828, 17 L.Ed.2d 705 (1967). Moreover, the Pennsylvania Supreme Court has long recognized and approved the compromising propensities of juries. Commonwealth v. Kellyon, supra, 122 A. at 168; Commonwealth v. Hoffman, supra, 266 A.2d at 732. This recognition dilutes the potency of the harmless error argument advanced by the Commonwealth.
VI.
Cognizant of the potential pervasive ramifications of the ruling we announce *347today, Judges Rosenn, Weis and the writer of this opinion are willing to consider the retroactivity issue. A majority of the court have concluded that the issue should not be resolved in this case.
In Witherspoon v. Illinois, 391 U.S. 510, 88 S.Ct. 1770, 20 L.Ed.2d 776 (1968), the Court squarely decided the retroactivity issue when it announced its ruling:
We have considered the suggestion that we should “give prospective application only to any new constitutional ruling in this area.” [We] have concluded that neither the reliance of law enforcement officials . . . nor the impact of a retroactive holding on the administration of justice warrants a decision against the fully retroactive application of the holding we announce today.
391 U.S. at 523 n. 22, 88 S.Ct. at 1777. And in its most recent pronouncement in the area of prisoners’ rights, Wolff v. McDonnell, 418 U.S. 539, 94 S.Ct. 2963, 41 L.Ed.2d 935 (1974), the Court had the opportunity to defer ruling on the retroactivity of its newly announced procedures. It did not. Instead, the Court followed its lead in Morrissey v. Brewer, 408 U.S. 471, 490, 92 S.Ct. 2593, 33 L.Ed.2d 484 (1972), and decided the retro-activity issue:
The Court of Appeals held that the due process requirements in prison disciplinary proceedings were to apply retroactively so as to require that prison records containing determinations of misconduct, not in accord with required procedures, be expunged. We disagree and reverse on this point.
The question of retroactivity of new procedural rules affecting inquiries into infractions of prison discipline is effectively foreclosed by this Court’s ruling in Morrissey that the due process requirements there announced were to be “applicable to future revocations of parole,” 408 U.S., at 490 [92 S.Ct. at 2604] (emphasis supplied). Despite the fact that procedures are related to the integrity of the fact-finding process, in the context of disciplinary proceedings, where less is generally at stake for an individual than at a criminal trial, great weight should be given to the significant impact a retroactivity ruling would have on the administration of all prisons in the country, and the reliance prison officials placed, in good faith, on prior law not requiring such procedures. During 1973, the Federal Government alone conducted 19,000 misconduct hearings, as compared with 1,173 parole revocation hearings, and 2,023 probation revocation hearings. If Morrissey-Scarpelli rules are not retroactive out of consideration for burden on federal and state officials, this case is a fortiori. We also note that a contrary holding would be very troublesome for the parole system since performance in prison is often a relevant criteria for parole. On the whole, we do not think that error was so pervasive in the system under the old procedures to warrant this cost or result.
418 U.S. at 573, 94 S.Ct. at 2983. Thus, we find no precedential impediment to reaching the retroactivity issue in this case.
In United States v. Zirpolo, 450 F.2d 424, 431-433 (3d Cir. 1971), we set forth in detail the basic teachings of the Supreme Court.24 Basically we observed:
In passing on the question of retroactivity, the Supreme Court considers three factors:
(a) the purpose to be served by the new standards, (b) the extent of *348the reliance by law enforcement authorities on the old standards, and (c) the effect on the administration of justice of a retroactive application of the new standards.
Stovall v. Denno, 388 U.S. 293, 297, 87 S.Ct. 1967, 1970 [18 L.Ed.2d 1199] (1967); Desist v. United States, 394 U.S. 244, 89 S.Ct. 1030, 22 L.Ed.2d 248 (1969); Johnson v. New Jersey, 384 U.S. 719, 86 S.Ct. 1772, 16 L.Ed. 2d 882 (1966); Tehan v. United States ex rel. Shott, 382 U.S. 406, 86 S.Ct. 459, 15 L.Ed.2d 453 (1966); Linkletter v. Walker, 381 U.S. 618, 85 S.Ct. 1731, 14 L.Ed.2d 601 (1965).
450 F.2d at 432.
“Foremost among . . . [the foregoing] factors is the purpose to be served by the new constitutional rule.” Desist v. United States, supra, 394 U.S. at 249, 89 S.Ct. at 1033 (footnote omitted). In United States v. Zirpolo, supra, we noted that “[generally, rulings not primarily designed to enhance the reliability of the fact-finding or truth-determining process have not been applied retroactively,” 450 F.2d at 432 and cases cited therein. We are dealing here only with those cases in which there is no evidence of passion or provocation.25 Therefore, our ruling does not go to the jury’s ability to determine the presence vel non of the elements of the crime but rather to the jury’s ability to exercise its “historically recognized mercy dispensing power.” Commonwealth v. Jones, supra, 319 A.2d at 149 (Nix, J.) Nothing we decide today affects the fact-finding process. We also recognize with Mr. Justice Brennan that “ ‘the question whether a constitutional rule of criminal procedure does or does not enhance the reliability of the fact-finding process at trial is necessarily a matter of degree.’ Johnson v. New Jersey . . . [384 U.S. 719], at 728-729, [86 S.Ct. at 1778], The extent to which a condemned practice infects the integrity of the truth-determining process at trial is a ‘question of probabilities.’ 384 U.S., at 729 [86 S.Ct. at 1778], Such probabilities must in turn be weighed against the prior justified reliance upon the old standard and the impact of retroactivity upon the administration of justice.” Stovall v. Denno, supra, 388 U.S. at 298, 87 S.Ct. at 1970.
The significant extent to which the Pennsylvania trial courts relied on the prior state of the law is obvious. See Commonwealth v. Matthews, supra; Commonwealth v. LaRue, supra; and Commonwealth v. Pavillard, supra. The decision we reach today was not foreshadowed by prior cases. Stovall v. Denno, supra, 388 U.S. at 299, 87 S.Ct. 1967. And we recognize that the application of full retroactivity could have a profound effect on the administration of criminal justice in Pennsylvania. The Supreme Court has relied on this factor in denying full retroactivity: United States v. Wade, 388 U.S. 218, 87 S.Ct. 1926, 18 L.Ed.2d 1149 (1967), and Gilbert v. California, 388 U.S. 263, 87 S.Ct. 1951, 18 L.Ed.2d 1178 (1967) (line-up cases) held non-retroactive in Stovall v. Denno, supra; McCarthy v. United States, 394 U.S. 459, 89 S.Ct. 1166, 22 L.Ed.2d 418 (1969) (on the correct procedure for acceptance of guilty plea) denied retroactive application in Halliday v. United States, 394 U.S. 831, 89 S.Ct. 1498, 23 L.Ed.2d 16 (1969).
All three considerations indicate that full retroactivity should not be accorded this decision. See eases collected in United States v. Zirpolo, supra, 450 F.2d at 431-433. As in Zirpolo, we would “conclude that our decision [should] apply only to those cases [in which a jury instruction for voluntary manslaughter was properly and timely requested and] if trials have been completed, are on direct ap*349peal [in the Pennsylvania courts] on this date.” 450 F.2d at 433.
The judgment of the district court granting a writ of habeas corpus will be affirmed unless the Commonwealth of Pennsylvania affords Matthews a new trial within such reasonable time as the district court shall fix following return of the mandate.
. Commonwealth v. Davis, 449 Pa. 468, 297 A.2d 817 (1972).
. Since May 2, 1974, Pennsylvania substantive law requires the manslaughter instruction to be given. In an equally divided court three justices (Roberts, Pomeroy and Man-derino) rested the decision on constitutional grounds. Three (Nix, Eagen and O’Brien) relied on an exercise of the court’s supervisory power: “We therefore, under our supervisory power, rule that henceforth a defendant under indictment of murder will be entitled, upon request, to have the jury advised of its power to return a verdict of voluntary manslaughter.” Commonwealth v. Jones, Pa., 319 A.2d 142, 148 (1974) (Nix, J.). Because the new Pennsylvania rule does not apply to this appellant we must still decide the constitutional issues raised in this appeal.
. [W]here the evidence would be sufficient to support a conviction of murder, the return of a verdict of voluntary manslaughter is strictly within the jury’s prerogative even in the absence of provocation and passion. Commonwealth v. Hoffman, 439 Pa. 348, 356-357, 266 A.2d 726, 731 (1970). See Commonwealth v. Butcher, 451 Pa. 359, 304 A.2d 150, 153 (1973). See also authorities collected in Commonwealth v. Jones, supra, separate opinions of Nix, J., p. 146 n. 2; Roberts, J., p. 144 n. 1.
. Commonwealth v. LaRue, 381 Pa. 113, 112 A.2d 362 (1955).
. The difference in culpability between first or second degree murder and voluntary manslaughter is reflected in the punishments which accompanied conviction of these respective offenses at the time of this offense. A conviction for first degree murder carried with it death or life imprisonment. Sanctions that were imposed upon one found guilty of second degree murder included imprisonment for a term not exceeding twenty years and a fine of up to ten thousand dollars. Act of June 24, 1939, P.L. 872, § 701, 18 Pa.Stat.Anno. § 4701. Punishment for voluntary manslaughter, in contrast, could not exceed twelve years imprisonment and six thousand dollars fine. Act of June 24, 1939, supra, § 703, 18 Pa.Stat.Anno. § 4703. Title 18 of the Consolidated Pennsylvania Statutes was amended December 6, 1972, effective June 6, 1973. The punishment for first degree murder remains the same. Act of December 6, 1972, P.L. -, No. 334, § 1, 18 Pa.Stat.Anno. § 1102 (1973). Punishment for second degree murder is imprisonment for not more than twenty years. Voluntary manslaughter is punishable by imprisonment for not more than ten years. Act of December 6, 1972, supra, § 1, 18 Pa.Stat.Anno. § 1103. The maximum punishment for voluntary manslaughter has been reduced by two years.
. At oral argument before this court, counsel for Matthews conceded that there was no evidence of provocation or passion presented at trial.
As we have noted, supra, n. 2, Pennsylvania trial judges must now grant the request for a voluntary manslaughter charge in all murder cases being tried on or after May 2, 1974. However, the above-described practice would still obtain in all cases not within the purview of the new rule.
. “By both tradition and constitutional mandate the jury is given the responsibility of determining guilt or innocence according to instructions of law delivered by the court.” United States v. Berrigan, 482 F.2d 171, 175 (3d Cir. 1973). Fundamental to the judicial system is the principle that it is the court, and not the jury, which defines the legal elements of the offense and limits the alternatives open to the jury in returning a verdict. As Justice Cohen stated in his dissent in Commonwealth v. Pavillard, supra, 220 A.2d at 811:
How is a jury able to exercise its power [to return a verdict of guilty of manslaughter] when it is never advised that it has such power?
. In Commonwealth v. Davis, supra, 297 A.2d at 819, Justice Pomeroy again argued:
[B]ecause the choice whether or not to charge is discretionary with the trial judge, and he has been furnished with no objective standards for his guidance, the challenged practice offends due process.
. The opinion in support of affirmance in Commonwealth v. Jones, supra, 319 A.2d at 149, answered the due process contention thusly:
The opinion in support of reversal predicates its constitutional objections on the assumption that under the rule existing at the time of this trial “the choice whether or not to charge [on voluntary manslaughter] is discretionary with the trial judge, and he has been furnished with no objective standards for his guidance.” We cannot accept the assumption upon which these arguments are premised. The rule in question was based upon a theory of lesser included' offenses. For this purpose, manslaughter was defined in the traditional sense. Thus, it was reasoned that the right to the charge existed only where evidence of provocation and passion could be found. Necessarily, where there was an absence of provocation and passion there was no right to such a charge. Cf., Keeble v. United States, 412 U.S. 205 [93 S.Ct. 1993, 36 L.Ed.2d 844] (1973).
This statement, however, defines the defendant’s right to a charge on voluntary manslaughter, while still leaving to the trial judge the ultimate decision on whether such a charge should be given. See infra, pp. 343-344.
*343Likewise, in Commonwealth v. Davis, supra, 297 A.2d at 821, Justice O’Brien speaking for himself, Chief Justice Jones and Justice Eagen, reasoned that under Pennsylvania law “a defendant is entitled to a charge on the law of manslaughter only when there is some evidence to support such a verdict.” He did not meet the constitutional issues raised but concluded that the facts of that felony-murder case rendered “any evidence of passion or provocation . . . irrelevant.” Id., at 822.
In Commonwealth v. Cannon, 453 Pa. 389, 309 A.2d 384 (1973), the defendant argued that there was evidence to support a verdict of manslaughter and therefore he was entitled to an instruction thereon. A majority of the court held that there was no evidence of passion or provocation and the refusal to instruct was not error; no constitutional issues were discussed. Justices Roberts, Pomeroy and Manderino dissented for the reasons expressed by Justices Roberts and Pomeroy in Matthews and Davis.
. One found guilty of a lesser offense is impliedly acquitted of the greater offense, thereby prohibiting retrial on the higher charge. Green v. United States, 355 U.S. 184, 78 S.Ct. 221, 2 L.Ed.2d 199 (1957).
. Section 1035 of the Revised Statutes and its successor provision P.R.Crim.Pro. 31(c), the federal “lesser offense” statutes.
. The Commonwealth cited various state court decisions from other jurisdictions. These cases also do not address themselves to the Pennsylvania practice.
. Commonwealth brief at 13.
. Commonwealth v. Jones, supra.
. “[T]he jury had the power, even though the evidence established murder, to find a voluntary manslaughter verdict.” Commonwealth v. Kellyon, supra, 122 A. at 167 (emphasis supplied).
. See footnote 3, supra. In Commonwealth v. Robinson, 305 Pa. 302, 157 A. 689, 692 (1931), the court approved the following instruction given by the trial judge in a murder case:
While we have defined to you the crime of voluntary manslaughter, we say to you, members of the jury, as we view the case, there is no evidence in it that would warrant a verdict of voluntary manslaughter, although, in the absence of evidence, it is within your power to render such a vei'-dict, because, in the crime of murder, the jury always has the right to fix the degree of the homicide.
. Bee cases cited in Commonwealth v. Jones, supra, Nix, J. at 319 A.2d 146 n. 1. We note that the opinions in support of affirmance in neither Commonwealth v. Jones, supra, nor Commonwealth v. Davis, supra, quoted any Pennsylvania cases with language to this effect.
. While the substantive ruling in Palko was overruled in Benton v. Maryland, 395 U.S. 784, 89 S.Ct. 2056, 23 L.Ed.2d 707 (1969), the essence of these remarks still. obtains. Cf., Roe v. Wade, 410 U.S. 113, 93 S.Ct. 705, 35 L.Ed.2d 147 (19731.
. Appellee was convicted in 1968, four years before the Supreme Court’s decision in Furman v. Georgia, 408 U.S. 238, 92 S.Ct. 2726, 33 L.Ed.2d 346 (1972).
. This opinion was authored by Justice O’Brien and he was joined by Chief Justice Jones and Justice Eagen. Although Chief Justice Jones took no part in the consideration or decision of Commonwealth v. Jones, supra, Justices O’Brien and Eagen were among the three justices opting for a supervisory rule.
. It appears that Pennsylvania law requires that a jury be told that they can return a verdict of second degree murder in all first degree murder cases. Commonwealth v. Gibbs, 366 Pa. 182, 76 A.2d 608 (1950); Commonwealth v. Davis, supra, 297 A.2d at 822 n. 1 (O’Brien, J., Opinion in Support of Affirmance).
. Commonwealth v. Matthews, supra, 285 A.2d at 517 (Pomeroy, J., dissenting).
a. Judge Kalodner in dissent argues that this is a felony/murder case and that “existence of passion and provocation . . . is of no relevance,” citing Commonwealth v. Meleskie, 278 Pa. 383, 123 A. 310 (1924). However, we are concerned here not with the existence or relevance of such evidence but rather with the jury’s ability to exercise its power to return a verdict of voluntary manslaughter, absent supportive evidence.
This power of the jury has not been denied in felony/murder cases. Bee, Commonwealth v. Butcher, supra. Indeed, we note that neither opinion in Commonwealth v. Jones, supra, explicity exempts felony/murder cases from the requirement that a charge on voluntary manslaughter be given upon request.
. See Roger Traynor’s incisive discussion, “Evaluating the Effect of Error: A Sliding Scale of Probabilities,” Traynor, The Riddle of Harmless Error (1970) 33-37.
. This case readily lends itself to the Link-letter analysis and it is therefore unnecessary to use the approach taken in Robinson v. Neil, 409 U.S. 505, 93 S.Ct. 876, 35 L.Ed. 2d 29 (1973). There, the Court noted that tlie Linhletter test “is simxjly not appropriate” in terms of nonprocedural guarantees. Id., at 508, 93 S.Ct. 876. Here we are dealing with a procedural rule.
. Where there is any evidence of passion or provocation in a murder case, a defendant is entitled to a charge on voluntary manslaughter. Commonwealth v. Flax, 331 Pa. 145, 200 A. 632, 636 (1938); Commonwealth v. Dews, 429 Pa. 555, 239 A.2d 382, 385 (1968).