delivered the opinion of the Court.
Wе granted certiorari in this case to decide whether a defendant accused of aiding and abetting in the commission of a federal offense may be convicted after the named principal has been acquitted of that offense.
I
In June 1977, petitioner Standefer was indicted on four counts of making gifts to a public official, in violation of 18 U. S. C. § 201 (f), and on five counts of aiding and abetting a revenue official in accepting compensation in addition to that authorized by law, in violation of 26 U. S. C. § 7214 (a) (2) and 18 U. S. C. § 2. 1 The indictment charged that *12 petitioner, as head of Gulf Oil Corp.’s tax department, had authorized payments for five vacation trips to Cyril Nieder-berger, who then was the Internal Revenue Service agent in charge of the audits of Gulf’s federal income tax returns. 2 Specifically, the indictment alleged that Gulf, on petitioner’s authorization, had paid for vacations for Niederberger in Pompano Beach (July 1971), Miami (January 1973), Ab-secon (August-September 1973), Pebble Beach (April 1974), and Las Vegas (June 1974). The four counts under 18 U. S. C. § 201 (f) related to the Miami, Absecon, Pebble Beach, and Las Vegas vacations; the five counts under 26 U. S. C. § 7214 (а)(2) and 18 U. S. C. § 2 were one for each vacation. 3
Prior to the filing of this indictment, Niederberger was separately charged in a 10-count indictment — two counts for each of the five vacations — with violating 18 U. S. C. § 201 (g) 4 and 26 U. S. C. §7214 (a)(2). In February 1977, Nieder-berger was tried on these charges. He was convicted on four counts of violating § 201 (g) in connection with the vacations in Miami, Absecon, Pebble Beach, and Las Vegas and of *13 two counts of violating § 7214 (a) (2) for the Pebble Beach and Las Vegas trips. He was acquitted on the § 201 (g) count involving the Pompano Beach trip and оn the three counts under § 7214 (a)(2) charging him with accepting payments from Gulf for trips to Pompano Beach, Miami, and Absecon. 5
In July 1977, following Niederberger’s trial and before the trial in his own case commenced, petitioner moved to dismiss the counts under § 7214 (a) (2) and 18 U. S. C. § 2 which charged him with" aiding and abetting Niederberger in connection with the Pompano Beach, Miami, and Absecon vacations. Petitioner argued that because Niederberger, the only named principal, had been acquitted of accepting unlawful compensation as to thosе vacations, he could not be convicted of aiding and abetting in the commission of those offenses. The District Court denied the motion.
Petitioner’s case then proceeded to trial on all nine counts. At trial, petitioner admitted authorizing payment for all five vacation trips, but testified that the trips were purely social and not designed to influence Niederberger in the performance of his official duties. The jury returned guilty verdicts on all nine counts. 6 Petitioner was sentenced to concurrent terms of six months’ imprisonment followed by two years’ probation; he was fined a total of $18,000 — $2,000 on each count.
Petitioner appealed his convictions to the Court of Appeals for the Third Circuit claiming,
inter alia,
that he could not
*14
be convicted of aiding and abetting a principal, Niederberger, when that principal had been acquitted of the charged offense. By a divided vote, the Court of Appeals, sitting en banc, rejected that contention.
Because the question рresented is one of importance to the administration of criminal justice on which the Courts of Appeals are in conflict, we granted certiorari.
7
II
Petitioner makes two main arguments: first, that Congress in enacting 18 U. S. C. § 2 did not intend to authorize prosecution of an aider and abettor after the principal has been acquitted of the offense charged; second, that, even if § 2 permits such a prosecution, the Government should be barred from relitigating the issue of whether Niederberger accepted unlawful compensation in cоnnection with the Pompano Beach, Miami, and Absecon vacations. 8 The first contention relies largely on the common law as it prevailed before the enactment of 18 U. S. C. § 2. The second rests on the contemporary doctrine of nonmutual collateral estoppel.
*15 A
At common law, the subject of principals and accessories was riddled with “intricate” distinctions. 2 J. Stephen, A History of the Criminal Law of England 231 (1883). In felony cases, parties to a crime were divided into four distinct categories: (1) principals in the first degree who actually perpetrated the offense; (2) principals in the second degree who were actually or constructively present at the scene of the crime and aided or abetted its commission; (3) accessories before the fact who aided or abetted the crime, but were not present at its commission; and (4) accessories after the fact who rendered assistance after the crime was complete. See W. LaFave & A. Scott, Criminal Law § 63 (1972); 4 W. Blackstone, Commentaries *33; Perkins, Parties to Crime, 89 U. Pa. L. Rev. 581 (1941). By contrast, misdеmeanor cases “d[id] not admit of accessaries either before or after the fact,”
United States
v.
Hartwell,
Because at early common law all parties to a felony received the death penalty, certain procedural rules developed tending to shield accessories from punishment. See LaFave & Scott, supra, at 499. Among them was one of special relevance to this case: the rule that an acсessory could not be convicted without the prior conviction of the principal offender. See 1 M. Hale, Pleas of the Crown *623-*624. Under this rule, the principal’s flight, death, or acquittal barred prosecution of the accessory. And if the principal were pardoned or his conviction reversed on appeal, the accessory’s conviction could not stand. In every way, “an accessory follow[ed], like a shadow, his principal.” 1 J. Bishop, Criminal Law § 666 (8th ed. 1892).
This procedural bar applied only to the prosecution of ac
*16
cessories in felony cases. In misdemeanor cases, where all рarticipants were deemed principals, a prior acquittal of the actual perpetrator did not prevent the subsequent conviction of a person who rendered assistance.
Queen
v.
Humphreys and Turner,
[1965] 3 All E. R. 689;
Queen
v.
Burton,
13 Cox C. C. 71, 75 (Crim. App. 1875). And in felony cases a principal in the second degree could be convicted notwithstanding the prior acquittal of the first-degree principal.
King
v.
Taylor and Shaw,
168 Eng. Rep. 283 (1785);
Queen
v.
Wallis,
1 Salk. 334, 91 Eng. Rep. 294 (K. B. 1703);
Brown
v.
State,
To overcome these judge-made rules, statutes were enacted in England and in the United States. In 1848 the Parliament enacted a statute providing that an accessory before the fact could be “indicted, tried, convicted, and punished in all respects like the Principal.” 11 & 12 Vic. ch. 46, § 1 (emphasis added). As interpreted, the statute permitted an accessory to be convicted “although the principal be acquitted.” Queen v. Hughes, Bell 242, 248, 169 Eng. Rep. 1245, 1248 (1860). Several state lеgislatures followed suit. 9 In 1899, *17 Congress joined this growing reform movement with the enactment of a general penal code for Alaska which abrogated the common-law distinctions and provided that “all persons *18 concerned in the commission of a crime, whether it be felony or misdemeanor, and whether they directly commit the act constituting the crime or aid and abet in its commission, though not present, are principals, and to be tried and punished as such.” Act of Mar. 3, 1899, § 186, 30 Stat. 1282. In 1901, Congress enacted a similar provision for the District of Columbia. 10
The enaсtment of 18 U. S. C. § 2 in 1909 was part and parcel of this same reform movement. The language of the statute, as enacted, unmistakably demonstrates the point:
“Whoever directly commits any act constituting an offense defined in any law of the United States, or aids, abets, counsels, commands, induces, or procures its commission, is a principal.” Act of Mar. 4, 1909, § 332, 35 Stat. 1152 (emphasis added). 11
*19
The statute “abolishe[d] the distinction between principals and accessories and [made] them all principals.”
Hammer
v.
United States,
The legislative history of § 2 confirms this understanding. The provision was recommended by the Commission to Revise and Codify the Criminal and Penal Laws of the United States as “[i]n accordance with the policy of recent legislation” by which “those whose relations to a crime wоuld be that of accessories before the fact according to the common law are made principals.” 1 Final Report of the Commission to Revise and Codify the Laws of the United States 118-119 (1906). The Commission’s recommendation was adopted without change. The House and Senate Committee Reports, in identical language, stated its intended effect:
“The committee has deemed it wise to make those who are accessories before the fact at common law principal offenders, thereby permitting their indictment аnd conviction for a substantive offense.
“At common law an accessory can not be tried without his consent before the conviction or outlawry of the principal except where the principal and accessory are tried together; if the principal could not be found or if he had been indicted and refused to plead, had been pardoned or died before conviction, the accessory could not be tried at all. This change of the existing law renders these obstacles to justice impossible.” S. Rep. Nо. 10, 60th *20 Cong., 1st Sess., pt. 1, p. 13 (1908); H. R. Rep. No. 2, 60th Cong., 1st Sess., pt. 1, p. 13 (1908). 12
And on the floor of the House of Representatives, Representative Moon, the Chairman of the Joint Select Committee, put the point simply: “We . . . have abolished the existing arbitrary distinction between felonies and misdemeanors.” 42 Cong. Rec. 585 (1908).
This history plainly rebuts petitioner’s contention that § 2 was not intended to authorize conviction of an aider and abettor after the principal had been acquitted of the offense charged. 13 With the enactment of that section, all partici- . pants in conduct violating a federal criminal statute are “principals.” As such, they are punishable for their criminal conduct; the fate of other participants is irrelevant. 14
*21 B
The doctrine of nonmutual collateral estoppel was unknown to the common law and to the Congress when it enacted § 2 in 1909.
15
It emerged in a civil case in 1942,
Bernhard
v.
Bank of America Nat. Trust & Savings Assn.,
Here, petitioner urges us to apply nonmutuаl estoppel against the Government; specifically he argues that the Gov *22 ernment should be barred from relitigating Niederberger’s guilt under § 7214 (a) (2) in connection with the vacation trips to Pompano Beach, Miami, and Absecon. That issue, he notes, was an element of his offense which was determined adversely to the Government at Niederberger’s trial. 16
This, however, is a criminal case, presenting considerations different from those in
Blonder-Tongue
or
Parklane Hosiery.
First, in a criminal case, the Government is often without the kind of “full and fair opportunity to litigate” that is a prerequisite of estoppel. Several aspects of our criminal law make this so: the prosecution’s discovery rights in criminal cases are limited, both by rules of court and constitutional privileges; it is prohibited from being granted a directed verdict or from obtaining a judgment notwithstanding the verdict no matter how clear the evidence in support of guilt, cf. Fed. Rule Civ. Proc. 50; it cannot secure a new trial on the ground that an acquittal was plainly contrary to the weight of the evidence, cf. Fed. Rule Civ. Proc. 59; and it cannot secure appellate reviеw where a defendant has been acquitted. See
United States
v.
Ball,
The absence of these remedial procedures in criminal cases permits juries to acquit out of compassion or compromise or because of “ 'their assumption of a power which they had no right to exercise, but to which they were disposed through lenity.’ ”
Dunn
v.
United States,
The application of nonmutual estoppel in criminal cases is also complicated by the existence of rules of evidence and exclusion unique to our criminal law. It is frequently true in criminal cases that evidence inadmissible against one defendant is admissible against another. The exclusionary rule, for example, may bar the Government from introducing evidence against one defendant because that evidence was obtained in violation of his constitutional rights. And the suppression of that evidence may result in an acquittal.
*24
The same evidence, however, may be admissible against other parties to the crime “whose rights were [not] violated.”
Alderman
v.
United States,
It is argued that this concern could be met on a case-by-case basis by conducting a pretrial hearing to determine whether any such evidentiary ruling had deprived the Government of an opportunity to present its case fully the first time around. That process, however, could prove protracted and burdensome. Under such a scheme, the Government presumably would be entitled to seek review of any adverse evidentiary ruling rendered in the first рroceeding and of any aspect of the jury charge in that case that worked to its detriment. Nothing short of that would insure that its opportunity to litigate had been “full and fair.” If so, the “pretrial hearing” would fast become a substitute for appellate review, and the very purpose of litigation economy that estoppel is designed to promote would be frustrated.
Finally, this case • involves an ingredient not present in either Blonder-T ongue or Parklane Hosiery, the important federal interest in the enforcement of the criminal law. Blonder-T ongue and Parklane Hosiery were disputes over private rights betweеn private litigants. In such , cases, no significant harm flows from enforcing a rule that affords a litigant only one full and fair opportunity to litigate an issue, and there is no sound reason for burdening the courts with repetitive litigation.
*25 That is not so here. The Court of Appeals opinion put the point well:
“[T]he purpose of a criminal court is not to provide a forum for the ascertainment of private rights. Rather it is to vindicate the public interest in the enforcement of the criminal law while at the same time safeguarding the rights of the individual defendant. The public interest in the accuracy and justice of criminal results is greater than the concern for judicial economy professed in civil cases and we are thus inclined to reject, at least as a general matter, a rule that would spread the effect of an erroneous acquittal to all those who participated in a particular criminal transaction. To plead crowded dockets as an excuse for not trying criminal defendants is in our view neither in the best interests of the courts, nor the public.”610 F. 2d, at 1093 .
In short, this criminal case involvеs “competing policy considerations” that outweigh the economy concerns that under-gird the estoppel doctrine. See Restatement (Second) of Judgments § 68.1 (e) and comments thereto (Tent. Draft No. 3, 1976); cf.
Commissioner
v.
Sunnen,
Ill
In denying preclusive effect to Niederberger’s acquittal, we do not deviate from the sound teaching that “justice must satisfy the appearance of justice.”
Offutt
v.
United States,
*26 Here, petitioner received a fair trial at which the Government bore the burden of proving beyond reasonable doubt that Niederberger violated 26 U. S. C. § 7214 (a) (2) and that petitioner aided and abetted him in that venture. He was entitled to no less — and to no more.
The judgment of the Court of Appeals is
Affirmed.
Notes
Title 18 U. S. C. § 201 (f) provides, in relevant part, as follows:
“Whoever, otherwise than as provided by law for the proper discharge of official duty, directly or indirectly gives, offers, or promises anything of value to any public official . . . for or because of any official act performed or to be performed by such public official ... [is guilty of an offense]
Title 26 U. S. C. § 7214 (a) (2) punishes:
“Any officer or employee of the United States acting in connection with any revenue law of the United States . . . who knowingly demands other or greater sums than are authorized by law, or receives any fee, compen *12 sation, or reward, except as by law prescribed, for the performance of any duty.”
Title 18 U. S. C. § 2 provides in relevant part:
“Whoever commits an offense against the United States or aids, abets, counsels, commands, induces or procures its commission, is punishable as a principal.”
The indictment also named Gulf Oil Corp. and Joseph Fitzgerald, a manager in Gulf’s tax department, as defendants. Gulf pleaded guilty and Fitzgerald nolo contendere to all nine counts.
It appears that the statute of limitations had run on any violation of 18 U. S. C. § 201 (f) in connection with the Pompano Beach vacation.
Title 18 U. S. C. §201 (g) punishes:
“Whoever, being a public official . . . , otherwise than as provided by law for the proper discharge of official duty, directly or indirectly asks, demands, exacts, solicits, seeks, aсcepts, receives, or agrees to receive anything of value for himself for or because of any official act performed or to be performed by him.”
Niederberger was sentenced to six months’ imprisonment followed by a five-year period of probation, and he was fined $5,000. His convictions were affirmed by the Court of Appeals.
United States
v.
Niederberger,
The jury was instructed that in order to render a guilty verdict on the § 7214 (a) counts it must determine (1) that Niederberger knowingly “received a fee, compensation or reward except as prescribed by law . . . for the performance ... of any duty” and (2) that petitioner “willfully aided and abetted [him].” App. 53a-54a, 57a.
The Courts of Appeals for the Fifth Circuit, the Ninth Circuit, and the District of Columbia Circuit have reached the same conclusion as the Third Circuit. See
United States
v.
Musgrave,
Petitioner also challenges the instructions to the jury on сriminal intent. We agree with the Court of Appeals that the instructions were correct.
By 1909, when § 2 was enacted, 13 States had enacted legislation providing that the acquittal of the actual perpetrator was not a bar to the conviction of one charged with giving him aid. See Cal. Stat., ch. 99, §§ 11, 12 (1850) (see
People
v.
Bearss,
Since then, at least 21 other States have enacted legislation with that effect. See 1977 Alа. Act No. 607, § 425; Ariz. Rev. Stat. Ann. § 13-304-1 (1978); Ark. Stat. Ann. § 41-304 (1977); Colo. Rev. Stat. §18-1-605 (1973) (see
Roberts
v.
People,
Eleven other States have enacted statutes that modify the common-law rule; these statutes have not been authoritatively construed on whether an accessory can be prosecuted after his principal’s acquittal. See Haw. Rev. Stat. § 702-225 (1976); Idaho Code § 19-1431 (1979); Mass. Gen. Laws Ann., ch. 274, § 3 (West 1970); Minn. Stat. § 609.05 (1978); Nev. Rev. Stat. § 195.040 (1979); Ohio Rev. Code Ann. § 2923.03 (1979); Ore. Rev. Stat. § 161.160 (1979); Vt. Stat. Ann., Tit. 13, § 3 (1974); Va. Code § 18.2-21 (1975); W. Va. Code § 61-11-7 (1977); Wyo. Stat. § 6-1-114 (1977).
Only four States — Maryland, North Carolina, Rhode Island, and Tennessee — clearly retain the common-law bar. See
State
v.
Ward,
The Model Penal Code provides that an accomplice may be convicted “though the person claimed to have committed the offense . . . has been *18 acquitted.” § 2.06(7) (Tent. Draft No. 3, 1955), and see comments 38-39 (Tent. Draft No. 1, 1953).
The provision is still in effect; it provides that all persons “aiding or abetting the principal offender, shall be charged as principals and not as accessories, the intent of this section being that as to all accessories before the fact the law heretofore applicable in cases of misdemeanor only shall apply to all crimes. . . .” Act of Mar. 3, 1901, § 908, 31 Stat. 1337; D. C. Code § 22-105 (1973) (emphasis added).
In 1951, the words “is a principal” were altered to read “is punishable as a principal.” That change was designed to eliminate all doubt that in the case of offenses whose prohibition is directed at members of specifiеd classes (e.
g.,
federal employees) a person who is not himself a member of that class may nonetheless be punished as a principal if he induces a person in that class to violate the prohibition. See S. Rep. No. 1020, 82d Cong., 1st Sess., 7-8 (1951). The change was fully consistent with congressional intent to treat accessories before the fact as principals and to abolish the common-law procedural bar. Indeed, by the time of the 1951 re-enactment, the Circuit Courts that had addressed the question had concluded that § 2 authorizes conviction of an aider and abettor notwithstanding the prior acquittal of the perpetrator of the offense. See
United States
v.
Klass,
Petitioner emphasizes the fact that the Committee Report fails to mention the common-law rule that the prior acquittal of a principal barred conviction of an accessory, and argues accordingly that Congress did not view that rule as an “obstacle to justice.” The Court of Appeals correctly rejected this argument, being unwilling to “apply the canon of statutory interpretation . . .
expressio unius, exchisio alterius
... to the language employed in a
committee report.”
It bears mention that even prior to 1909 petitioner would not have prevailed in his attempt to bar prosecution on the § 7214 (a) (2) cоunts. As the Government notes, the version of 26 U. S. C. § 7214 then in effect defined the offense to be a misdemeanor. See Rev. Stat. §3169 (1878). Hence, the prior acquittal of his principal would not have barred petitioner’s prosecution. And because petitioner accompanied Niederberger on four of five trips and therefore was “present” at the scene of the crime, see Tr. 1018-1020, 1024-1027, 1034-1036, 1096, he could have been convicted at common law for those crimes even if the offense had been designated a felony.
Nothing in
Shuttlesworth
v.
Birmingham,
In 1912, in
Bigelow
v.
Old Dominion Copper Co.,
Petitioner does not contend that the Constitution prevents the Government from prosecuting him on the three § 7214 (a) (2) counts as to which Niederberger was acquitted. Nothing in the Double Jeopardy Clause or the Due Process Clause forecloses putting petitioner on trial as an aider and abettor simply because another jury has determined that his principal was not guilty of the offenses charged. Cf.
Ashe
v.
Swenson,
Niederberger’s case demonstrates the pоint. As to the Absecon and Miami vacations, the jury convicted Niederberger of receiving something of value “because of any official act performed ... by him,” 18 U. S. C. § 201 (g), but acquitted him of receiving “any fee, compensation, or reward ... for the performance of any duty,” 26 U. S. C. § 7214 (a) (2). No explanation has been offered for these seemingly irreconcilable determinations. This inconsistency is reason, in itself, for not giving preclusive effect to the acquittals on the Absecon and Miami counts. See Restatement (Second) of Judgments §88(4) (Tent. Draft No. 3, 1976). See also
This is not to suggest that the availability of appellate review is always an essential predicate of estoppel. See
Johnson Co.
v.
Wharton,
Indeed, as the Court of Appeals observed, to give the first case pre-clusive effect would undermine the
Alderman
rule by affording a defendant whose rights were not violated the benefits of suppression. See
