To ensure the separation of powers, the Constitution prohibits Congress from issuing Bills of Attainder. Only the court system is permitted to determine whether someone has violated a law and to issue punishment. Similarly, Ex Post Facto laws are prohibited as well. Congress cannot pass a law that retroactively creates a crime where none existed before.
"No Bill of Attainder or ex post facto Law shall be passed."
United States Library of Congress, The Constitution of the United States of America: Analysis and Interpretation
"Bills of attainder . . . are such special acts of the legislature, as inflict capital punishments upon persons supposed to be guilty of high offences, such as treason and felony, without any conviction in the ordinary course of judicial proceedings. If an act inflicts a milder degree of punishment than death, it is called a bill of pains and penalties. . . . In such cases, the legislature assumes judicial magistracy, pronouncing upon the guilt of the party without any of the common forms and guards of trial, and satisfying itself with proofs, when such proofs are within its reach, whether they are conformable to the rules of evidence, or not. In short, in all such cases, the legislature exercises the highest power of sovereignty, and what may be properly deemed an irresponsible despotic discretion, being governed solely by what it deems political necessity or expediency, and too often under the influence of unreasonable fears, or unfounded suspicions."1 The phrase "bill of attainder," as used in this clause and in clause 1 of § 10, applies to bills of pains and penalties as well as to the traditional bills of attainder.2
The prohibition embodied in this clause is not to be narrowly construed in the context of traditional forms but is to be interpreted in accordance with the designs of the framers so as to preclude trial by legislature, which would violate the separation of powers.3 The clause thus prohibits all legislative acts, "no matter what their form, that apply either to named individuals or to easily ascertainable members of a group in such a way as to inflict punishment on them without a judicial trial. . . ."4 That the Court has applied the clause dynamically is revealed by a consideration of the three cases in which acts of Congress have been struck down as violating it.5 In Ex parte Garland,6 the Court struck down a statute that required attorneys to take an oath that they had taken no part in the Confederate rebellion against the United States before they could practice in federal courts. The statute, and a state constitutional amendment requiring a similar oath of persons before they could practice certain professions,7 were struck down as legislative acts inflicting punishment on a specific group the members of which had taken part in the rebellion and therefore could not truthfully take the oath. The clause then lay unused until 1946 when the Court used it to strike down a rider to an appropriations bill forbidding the use of money appropriated in the bill to pay the salaries of three named persons whom the House of Representatives wished discharged because they were deemed to be "subversive."8
Then, in United States v. Brown,9 a sharply divided Court held void as a bill of attainder a statute making it a crime for a member of the Communist Party to serve as an officer or as an employee of a labor union. Congress could, Chief Justice Warren wrote for the majority, under its commerce power, protect the economy from harm by enacting a prohibition generally applicable to any person who commits certain acts or possesses certain characteristics making him likely in Congress's view to initiate political strikes or other harmful deeds and leaving it to the courts to determine whether a particular person committed the specified acts or possessed the specified characteristics. It was impermissible, however, for Congress to designate a class of persons—members of the Communist Party—as being forbidden to hold union office.10 The dissenters viewed the statute as merely expressing in shorthand the characteristics of those persons who were likely to utilize union responsibilities to accomplish harmful acts; Congress could validly conclude that all members of the Communist Party possessed those characteristics.11
The majority's decision in Brown cast in doubt certain statutes and certain statutory formulations that had been held not to constitute bills of attainder. For example, a predecessor of the statute struck down in Brown, which had conditioned a union's access to the NLRB upon the filing of affidavits by all of the union's officers attesting that they were not members of or affiliated with the Communist Party, had been upheld,12 and although Chief Justice Warren distinguished the previous case from Brown on the basis that the Court in the previous decision had found the statute to be preventive rather than punitive,13 he then proceeded to reject the contention that the punishment necessary for a bill of attainder had to be punitive or retributive rather than preventive,14 thus undermining the prior decision. Of much greater significance was the effect of the Brown decision on "conflict-of-interest" legislation typified by that upheld in Board of Governors v. Agnew.15 The statute there forbade any partner or employee of a firm primarily engaged in underwriting securities from being a director of a national bank.16 Chief Justice Warren distinguished the prior decision and the statute on three grounds from the statute then under consideration. First, the union statute inflicted its deprivation upon the members of a suspect political group in typical bill-of-attainder fashion, unlike the statute in Agnew. Second, in the Agnew statute, Congress did not express a judgment upon certain men or members of a particular group; it rather concluded that any man placed in the two positions would suffer a temptation any man might yield to. Third, Congress established in the Agnew statute an objective standard of conduct expressed in shorthand which precluded persons from holding the two positions.
Apparently withdrawing from the Brown analysis in upholding a statute providing for governmental custody of documents and recordings accumulated during the tenure of former President Nixon,17 the Court set out a rather different formula for deciding bill of attainder cases.18 The law specifically applied only to President Nixon and directed an executive agency to assume control over the materials and prepare regulations providing for ultimate public dissemination of at least some of them; the act assumed that it did not deprive the former President of property rights but authorized the award of just compensation if it should be judicially determined that there was a taking.
First, the Court denied that the clause denies the power to Congress to burden some persons or groups while not so treating all other plausible individuals or groups; even the present law's specificity in referring to the former President by name and applying only to him did not condemn the act because "he constituted a legitimate class of one" on whom Congress could "fairly and rationally" focus.19 Second, even if the statute's specificity did bring it within the prohibition of the clause, the lodging of Mr. Nixon's materials with the GSA did not inflict punishment within the meaning of the clause.
This analysis was a three-pronged one: 1) the law imposed no punishment traditionally judged to be prohibited by the clause; 2) the law, viewed functionally in terms of the type and severity of burdens imposed, could rationally be said to further nonpunitive legislative purposes; and 3) the law had no legislative record evincing a congressional intent to punish.20 That is, the Court, looking "to its terms, to the intent expressed by Members of Congress who voted its passage, and to the existence or nonexistence of legitimate explanations for its apparent effect," concluded that the statute served to further legitimate policies of preserving the availability of evidence for criminal trials and the functioning of the adversary legal system and in promoting the preservation of records of historical value, all in a way that did not and was not intended to punish the former President.
The clause protects individual persons and groups who are vulnerable to nonjudicial determinations of guilt and does not apply to a state; nor does a state have standing to invoke the clause for its citizens against the Federal Government.21
Both federal and state governments are prohibited from enacting ex post facto laws22 and the Court applies the same analysis whether the law in question is a federal or a state enactment. When these prohibitions were adopted as part of the original Constitution, many persons understood the term ex post facto laws to "embrace all retrospective laws, or laws governing or controlling past transactions, whether . . . of a civil or a criminal nature."23 But in the early case of Calder v. Bull,24 the Supreme Court decided that the phrase, as used in the Constitution, was a term of art that applied only to penal and criminal statutes. But, although it is inapplicable to retroactive legislation of any other kind,25 the constitutional prohibition may not be evaded by giving a civil form to a measure that is essentially criminal.26 Every law that makes criminal an act that was innocent when done, or that inflicts a greater punishment than the law annexed to the crime when committed, is an ex post facto law within the prohibition of the Constitution.27 A prosecution under a temporary statute that was extended before the date originally set for its expiration does not offend this provision even though it is instituted subsequent to the extension of the statute's duration for a violation committed prior thereto.28 Because this provision does not apply to crimes committed outside the jurisdiction of the United States against the laws of a foreign country, it is immaterial in extradition proceedings whether the foreign law is ex post facto or not.29
The issue of whether a law is civil or punitive in nature is essentially the same for ex post facto and for double jeopardy analysis.30 "A court must ascertain whether the legislature intended the statute to establish civil proceedings. A court will reject the legislature's manifest intent only where a party challenging the Act provides the clearest proof that the statutory scheme is so punitive in either purpose or effect as to negate the State's intention."31 A statute that has been held to be civil and not criminal in nature cannot be deemed punitive "as applied" to a single individual.32
A variety of federal laws have been challenged as ex post facto. A statute that prescribed as a qualification for practice before the federal courts an oath that the attorney had not participated in the Rebellion was found unconstitutional because it operated as a punishment for past acts.33 But a statute that denied to polygamists the right to vote in a territorial election was upheld even as applied to one who had not contracted a polygamous marriage and had not cohabited with more than one woman since the act was passed, because the law did not operate as an additional penalty for the offense of polygamy but merely defined it as a disqualification of a voter.34 A deportation law authorizing the Secretary of Labor to expel aliens for criminal acts committed before its passage is not ex post facto because deportation is not a punishment.35 For this reason, a statute terminating payment of old-age benefits to an alien deported for Communist affiliation also is not ex post facto, for the denial of a non-contractual benefit to a deported alien is not a penalty but a regulation designed to relieve the Social Security System of administrative problems of supervision and enforcement likely to arise from disbursements to beneficiaries residing abroad.36 Likewise, an act permitting the cancellation of naturalization certificates obtained by fraud prior to the passage of the law was held not to impose a punishment, but instead simply to deprive the alien of his ill-gotten privileges.37
A change of the place of trial of an alleged offense after its commission is not an ex post facto law. If no place of trial was provided when the offense was committed, Congress may designate the place of trial thereafter.38 A law that alters the rule of evidence to permit a person to be convicted upon less or different evidence than was required when the offense was committed is invalid,39 but a statute that simply enlarges the class of persons who may be competent to testify in criminal cases is not ex post facto as applied to a prosecution for a crime committed prior to its passage.40