Opinion of
Mr. Justice Frankfurter,
in which Mr. Justice Clark, Mr. Justice Whittaker and Mr. Justice Stewart join, and judgment of the Court, announced by Mr. Justice Brennan.
This is an action brought in the Supreme Court of Richmond County, New York, for a declaratory judgment regarding the constitutional validity of § 8 of the New York Waterfront Commission Act of 1953 (N. Y. Laws [145]*1451953, cc. 882, 883; McK. Unconsol. Laws, § 6700aa et seq.), and for an injunction restraining its operation. The section is claimed to be in conflict with the Supremacy Clause of the United States Constitution; it is also challenged under the Due Process Clause of the Fourteenth Amendment, and as an ex post facto law and bill of attainder forbidden by Art. I, § 10, of the Constitution.
The Waterfront Commission Act formulates a detailed scheme for governmental supervision of employment on the waterfront in the Port of New York. The relevant part of the specific provision, § 8, under attack follows:
“No person shall solicit, collect or receive any dues, assessments, levies, fines or contributions within the state from employees registered or licensed pursuant to the provisions of this act [pi'er superintendents, hiring agents, longshoremen and port watchmen] for or on behalf of any labor organization representing any such employees, if any officer or agent of such organization has been convicted by a court of the United States, or any state or territory thereof, of a felony unless he has been subsequently pardoned therefor by the governor or other appropriate authority of the state or jurisdiction in which such conviction was had or has received a certificate of good conduct from the board of parole pursuant to the provisions of the executive law to remove the disability.”
The complaint upon which this action is based makes the following allegations. Appellant was a member, and beginning in 1950 had been Secretary-Treasurer, of Local 1346, International Longshoremen’s Association, a labor organization with offices in Richmond County, New York, representing “employees registered or licensed pursuant to” the Waterfront Commission Act. As Secretary-Treasurer appellant had control of the Local’s funds and also served as a bargaining representative. In 1920 appellant [146]*146had pleaded guilty to a charge of grand larceny in New York and had received a suspended sentence. It is not alleged that appellant has ever applied for or received a pardon or a “certificate of good conduct.” Three years after the enactment of the Waterfront Commission Act, in 1956, the President of the International Longshoremen’s Association was informed by the appellee, who was and is the District Attorney of Richmond County, New York, that because of appellant’s conviction § 8 of the Act prohibited any person from collecting dues on behalf of Local 1346, so long as appellant remained its officer or agent. Appellee threatened to prosecute anyone collecting dues for the Local while appellant remained its officer. By reason of § 8 and this threat appellant was suspended as an officer of Local 1346, whereupon he brought this action.
The appellee moved to dismiss the complaint, and for judgment on the pleadings in his favor. This motion was granted. The court, holding that appellant’s 1920 conviction was a conviction for a felony within the meaning of § 8, sustained the validity of that section. 11 Misc. 2d 661, 166 N. Y. S. 2d 751. This judgment was affirmed by the Appellate Division of the Supreme Court, 5 A. D. 2d 603, 174 N. Y. S. 2d 596, and by the Court of Appeals of New York, 5 N. Y. 2d 236, 157 N. E. 2d 165. See also Hazelton v. Murray, 21 N. J. 115, 121 A. 2d 1. Since a statute of a State has been upheld by the highest court of the State against a federal constitutional attack, the case is properly here on appeal. 361 U. S. 806.1
[147]*147Due consideration of the constitutional claims that are made requires that § 8 be placed in the context of the structure and history of the legislation of which it is a part. The New York Waterfront Commission Act was an endeavor by New York and New Jersey to cope with long-standing evils on their joint waterfront in the Port of New York. The solution which was evolved between the two States embodies not only legislation by each but also joint action by way of a constitutional compact between them, approved by Congress, including the establishment of a bi-state Waterfront Commission.
For years the New York waterfront presented a notoriously serious situation. Urgent need for drastic reform was generally recognized. Thoroughgoing investigations of the mounting abuses were begun in 1951 by the New York State Crime Commission and the Law Enforcement Council of New Jersey. After extensive hearings, the New York Crime Commission in May 1953 published a detailed report (4th Report of the New York State Crime Commission, New York State Leg. Doc. No. 70 (1953)) on the evils its investigation disclosed and the legislative remedies these were thought to require. The Commission reported that the skulduggeries on the waterfront were largely due to the domination over waterfront employment gained by the International Longshoremen's Association, as then conducted. Its employment practices easily led to corruption, and many of its officials participated in dishonesties. The presence on the waterfront of convicted felons in many influential positions was an important causative factor in this appalling situation. It was thus described to Congress in the compact submitted by New York and New Jersey for its consent:
. . the conditions under which waterfront labor is employed within the Port of New York district are depressing and degrading to such labor, resulting [148]*148from the lack of any systematic method of hiring, the lack of adequate information as to the availability of employment, corrupt hiring practices and the fact that persons conducting such hiring are frequently criminals and persons notoriously lacking in moral character and integrity and neither responsive or responsible to the employers nor to the uncoerced will of the majority of the members of the labor organizations of the employees; that as a result waterfront laborers suffer from irregularity of employment, fear and insecurity, inadequate earnings, an unduly high accident rate, subjection to borrowing at usurious rates of interest, exploitation and extortion as the price of securing employment and a loss of respect for the law; that not only does there result a destruction of the dignity of an important segment of American labor, but a direct encouragement of crime which imposes a levy of greatly increased costs on food, fuel and other necessaries handled in and through the Port of New York district.
. . many of the evils above described result not only from the causes above described but from the practices of public loaders at piers and other waterfront terminals; that such public loaders serve no valid economic purpose and operate as parasites exacting a high and unwarranted toll on the flow of commerce in and through the Port of New York district, and have used force and engaged in discriminatory and coercive practices including extortion against persons not desiring to employ them; . . .
“. . . stevedores have engaged in corrupt practices to induce their hire by carriers of freight by water and to induce officers and representatives of labor organizations to betray their trust to the members of such labor organizations.” 67 Stat. 541-542.
[149]*149Shortly after the Crime Commission submitted its report, the Governor of New York conducted hearings based upon the Crime Commission report. As a result, a Waterfront Commission Act was introduced into and passed by the Legislatures of both States in June 1953. N. Y. Laws 1953, cc. 882, 883; N. J. Laws 1953, cc. 202, 203.
Part I of both Acts constitutes what became the compact between the two States. This is the heart of the legislation. It establishes as a bi-state agency a Waterfront Commission of New York Harbor with power to license, register and regulate the waterfront employment of pier superintendents, hiring agents, longshoremen and port watchmen, and to license and regulate stevedores. It entirely prohibits one class of waterfront employment, public loading, found to be unnecessary and particularly infested with corruption. Manifestly, one of the main aims of the compact is to keep criminals away from the waterfront. The issue of licenses to engage in waterfront occupations, or the right to be registered, depends upon findings by the Commission of good character. In particular, past convictions for certain felonies constitute specific disabilities for each occupation, with discretion in the Commission to lift the disability, except in the case of port watchmen, where it constitutes an absolute bar to waterfront employment. A new procedure for the employment of longshoremen is also provided under the supervision of the Commission, replacing the archaic, corrupt “shape-up.”
Under the requirement of Art. I, § 10, of the Constitution the compact was submitted to the Congress for its consent, and it was approved. This was no perfunctory consent. Congress had independently investigated the evils that gave rise to the Waterfront Commission Acts, and the Subcommittee of the Senate Committee on Inter[150]*150state and Foreign Commerce had in a Report endorsed the state legislative solution embodied in these Acts. See S. Rep. No. 653, 83d Cong., 1st Sess., pp. 49-50. After the compact’s submission to Congress, hearings were held upon it by the Committee on the Judiciary of the House of Representatives, at which arguments were made by interested parties for and against the compact. Approval was recommended by both the House Judiciary Committee and the Senate Committee on Interstate and Foreign Commerce. The House Committee concluded that “ [t]he extensive evidence of crime, corruption, and racketeering-on the waterfront of the port of New York, as disclosed by the State investigations reported to this committee at its hearings and by the recent report of the Senate Committee on Interstate and Foreign Commerce [S. Rep. No. 653, supra], has made it clear beyond all question that the plan proposed by the States of New York and New Jersey to eradicate those public evils is urgently needed.” H. R. Rep. No. 998, 83d Cong., 1st Sess., p. 1. The Senate Committee Report stated its conclusion in similar terms. S. Rep.. No. 583, 83d Cong., 1st Sess., p. 1. The compact was approved by Congress in August 1953. Act of Aug. 12, 1953, 67 Stat. 541, c. 407.
In addition to the compact, New York enacted, as Parts II and III of its 1953 Waterfront Commission Act, supplementary legislation dealing, in most part, with the administration of New York’s responsibility under the compact. This supplementary legislation also contains two substantive provisions in furtherance of the objectives of the compact, but not calling for bi-state enforcement, and thus not included in the compact. These are § 8, which is here challenged, and a prohibition against loitering on the waterfront. New Jersey enacted a supplementary provision essentially similar to § 8. N. J. Laws, 1953, c. 202, § 8. Although § 8 does not require enforcement by the bi-state Waterfront Commission, and was [151]*151therefore not formally submitted as part of the compact to Congress, in giving its approval to the compact Congress explicitly gave its authority to such supplementary legislation in accord with the objectives of the compact by providing in the clause granting consent “[t]hat the consent of Congress is hereby given to the compact set forth . . . and to the carrying out and effec-tuation of said compact, and enactments in furtherance thereof.”
In giving this authorization Congress was fully mindful of the specific provisions of § 8. Not only had § 8 already been enacted by the States as part of the Waterfront Commission Acts when the compact was submitted to Congress, but, in the hearings held before the House Committee on the Judiciary, it was specifically urged by counsel for the International Longshoremen’s Association, as a ground of opposition to congressional consent, that approval of the compact by Congress would carry with it sanction of § 8. See Hearing before Subcommittee No. 3 of the Committee on the Judiciary, House of Representatives, 83d Cong., 1st Sess., on H. R. 6286, H. R. 6321, H. R. 6343, and S. 2383, p. 136. The ground of objection to the section which is appellant’s primary reliance here, namely, that it conflicts with existing federal labor policy, was urged as ground for rejecting the compact. It is in light of this legislative history that the compact was approved, and that congressional consent was given to “enactments in furtherance thereof.”
With this background in mind, we come to consider appellant’s objection that § 8 is in conflict with and therefore pre-empted by the National Labor Relations Act, specifically §§ 1 and 7 of that Act, 29 U. S. C. §§ 151, 157. The argument takes this course. Section 1 of the National Labor Relations Act declares a congressional purpose to protect “the exercise by workers of full freedom of association, self-organization, and designation of rep[152]*152resentatives of their own choosing, for the purpose of negotiating the terms and conditions of their employment or other mutual aid or protection.” Section 7 grants employees “the right ... to bargain collectively through representatives of their own choosing.” Under § 8 of the Waterfront Commission Act, waterfront employees do not have complete freedom of choice in the selection of their representatives, for if they choose a convicted felon the union is disabled from collecting dues. Thus, it is said, with reliance on Hill v. Florida, 325 U. S. 538, there is a conflict and the state legislation must fall.
This is not a situation where the operation of a state statute so obviously contradicts a federal enactment that it would preclude both from functioning together or, at least, would impede the effectiveness of the federal measure. Section 8 of the Waterfront Commission Act does not operate to deprive waterfront employees of opportunity to choose bargaining representatives. It does disable them from choosing as their representatives ex-felons who have neither been pardoned nor received “good conduct” certificates. The fact that there is some restriction due to the operation of state law does not settle the issue of pre-emption. The doctrine of pre-emption does not present a problem in physics but one of adjustment because of the interdependence of federal and state interests and of the interaction of federal and state powers. Obviously, the National Labor Relations Act does not exclude every state policy that may in fact restrict the complete freedom of a group of employees to designate “representatives of their own choosing.” For example, by reason of the National Labor Relations Act a State surely is not forbidden to convict and imprison a defendant in a criminal case merely because he is a union official and therefore could not serve as a bargaining representative.
[153]*153It would misconceive the constitutional doctrine of preemption — of the exclusion because of federal regulation of what otherwise is conceded state power — to decide this case mechanically on an absolute concept of free choice of representatives on the part of employees, heedless of the light that Congress has shed for our guidance. The relevant question is whether we may fairly infer a congressional purpose incompatible with the very narrow and historically explained restrictions upon the choice of a bargaining representative embodied in § 8 of the New York Waterfront Commission Act. Would Congress, with a lively regard for its own federal labor policy, find in this state enactment a true, real frustration, however dialectically plausible, of that policy?
In light of the purpose, scope and background of this New York legislation and Congress’ relation to it, such an inference of incompatibility has no foundation. In this case we need not imaginatively summon the likely reaction of Congress to the state legislation, as a basis for ascertaining whether due regard for congressional purpose bars the state regulation. Here the States presented their legislative program to cope with an urgent local problem to the Congress, and the Congress unambiguously supported what is at the core of this reform. Had § 8 been written into the compact, even the most subtle casuistry could not conjure up a claim of pre-emption.
Here the challenged state legislation was not in terms approved by Congress, but was part of the legislative history and of the revealed purpose of the compact which was approved. Formal inclusion of § 8 in the compact was not called for since its enforcement was to be unilateral on the part of each State. Both New York and New Jersey enacted § 8 at the time they enacted the proposed compact. Section 8 is the same kind of regulation as is contained in the compact: it effectively disqualifies [154]*154ex-felons from waterfront union office, just as the compact makes prior conviction of certain felonies a bar to waterfront employment, unless there is a favorable exercise of executive discretion. The total state legislative program represents a drastic effort to rid the waterfront of criminal elements by generally excluding ex-felons. What sensible reason is there to suppose that Congress would approve the major part of this local effort, as it has expressly done through its approval of the compact, and disapprove its application to union officials who, as history proved, had emerged as a powerful and corrupting influence on the waterfront second to none?
This is not all. As we have seen, § 8 was brought to the attention of Congress as part of the legislation which would come into effect as an adjunct to the compact, and the objection was raised at that time and not heeded that § 8 unduly interfered with federal labor policy. Finally, it is of great significance that in approving the compact Congress did not merely remain silent regarding supplementary legislation by the States. Congress expressly gave its consent to such implementing legislation not formally part of the compact. This provision in the consent by Congress to a compact is so extraordinary as to be unique in the history of compacts. Of all the instances of congressional approval of state compacts — the process began in 1791, Act of Feb. 4, 1791, 1 Stat. 189, with more than one hundred compacts approved since — we have found no other in which Congress expressly gave its consent to implementing legislation. It is instructive that this unique provision has occurred in connection with approval of a compact dealing with the prevention of crime where, because of the peculiarly local nature of the problem, the inference is strongest that local policies are not to be thwarted.
The sum of these considerations is that it would offend reason to attribute to Congress a purpose to pre-empt the [155]*155state regulation contained in § 8. The decision in Hill v. Florida, 325 U. S. 538, in no wise obstructs this conclusion. An element most persuasive here, congressional approval of the heart of the state legislative program explicitly-brought to its attention, was not present in that case. Nor was it true of Hill v. Florida, as it is here, that the challenged state legislation was part of a program, fully canvassed by Congress through its own investigations, to vindicate a legitimate and compelling state interest, namely, the interest in combatting local crime infesting a particular industry.
Appellant also asks us to find evidence of federal preemption of § 8 of the Waterfront Commission Act in the enactment by Congress of the Labor-Management Reporting and Disclosure Act of 1959, 73 Stat. 519. Title V of the 1959 Act imposes restrictions upon union officers, and defines qualifications for such officers. Specifically, § 504 (a) provides that “[n]o person . . . who has been convicted of, or served any part of a prison term resulting from his conviction of [a group of serious felonies] . . . shall serve — (1) as an officer, director, trustee, member of any executive board or similar governing body, business agent, manager, organizer, or other employee (other than as an employee performing exclusively clerical or custodial duties) of any labor organization ... for five years after . . . such conviction or after the end of such imprisonment, unless prior to the end of such five-year period, in the case of a person so convicted or imprisoned, (A) his citizenship rights, having been revoked as a result of such conviction, have been fully restored, or (B) the Board of Parole of the United States Department of Justice determines that such person’s service in any capacity referred to in clause (1) . . . would not be contrary to the purposes of this Act.”
[156]*156The fact that Congress itself has thus imposed the same type of restriction upon employees' freedom to choose bargaining representatives as New York seeks to impose through § 8, namely, disqualification of ex-felons for union office, is surely evidence that Congress does not view such a restriction as incompatible with its labor policies. Appellant, however, argues that any state disablement from holding union office on account of a prior felony conviction, such as § 8, which has terms at variance with § 504 (a), is impliedly barred by it. Just the opposite conclusion is indicated by the 1959 Act, which reflects congressional awareness of the problems of pre-emption in the area of labor legislation, and which did not leave the solution of questions of pre-emption to inference. When Congress meant pre-emption to flow from the 1959 Act it expressly so provided. Sections 205 (c) and 403, set out in the margin,2 are express provisions excluding the operation of state law,, supplementing provisions for new federal regulation. No such pre-emption provision was provided in connection with § 504 (a). That alone is sufficient reason for not deciding that § 504 (a) preempts § 8 of the Waterfront Commission Act. In addition, two sections of the 1959 Act, both relevant to this case, affirmatively preserve the operation of state laws. [157]*157That § 504 (a) was not to restrict state criminal law enforcement regarding the felonies there enumerated as federal bars to union office is provided by § 604 of the 1959 Act': “Nothing in this Act shall be construed to impair or diminish the authority of any State to enact and enforce general criminal laws with respect to [the same group of serious felonies, with the exception of exclusively federal violations, which are listed in § 504 (a)].” And to make the matter conclusive, § 603 (a) is an express disclaimer of pre-emption of state laws regulating the responsibilities of union officials, except where such pre-emption is expressly provided in the 1959 Act. Section 603 (a) provides: “Except as explicitly provided to the contrary, nothing in this Act shall reduce or limit the responsibilities of any labor organization or any officer, agent, shop steward, or other representative of a labor organization . . . under the laws of any State . . . .” In view of this explicit and elaborate treatment of pre-emption in the 1959 Act, no inference can possibly arise that § 8 is impliedly pre-empted by § 504 (a).
Appellant’s argument that § 8 of the Waterfront Commission Act is contrary to the Due Process Clause of the Fourteenth Amendment depends, as it must, upon the proposition that barring convicted felons from waterfront union office, unless they are pardoned, or receive a “good conduct” certificate, is not, in the context of the particular circumstances which gave rise to the legislation, a reasonable means for achieving a legitimate state aim, namely, eliminating corruption on the waterfront.
In disqualifying all convicted felons from union office unless executive discretion is exercised in their favor, § 8 may well be deemed drastic legislation. But in the view of Congress and the two States involved the situation on the New York waterfront regarding the presence and influence of ex-convicts called for drastic action. Legislative investigation had established that the presence of [158]*158ex-convicts on the waterfront was not a minor episode but constituted a principal corrupting influence. The Senate Subcommittee which investigated for Congress conditions on the New York waterfront found that “[criminals whose long records belie any suggestion that they can be reformed have been monopolizing controlling positions in the International Longshoremen's Association and in local unions. ’ Under their regimes gambling, the narcotics traffic, loansharking, shortganging, payroll 'phantoms,' the 'shakedown' in all its forms — and the brutal ultimate of murder — have flourished, often virtually unchecked.'' S. Rep. No. 653, 83d Cong., 1st Sess. (1953), p. 7.
In light of these findings, and other evidence to the same effect,3 the Congress approved as appropriate if indeed not necessary a compact, one of the central devices of which was to bar convicted felons from waterfront employment, and from acting as stevedores employing others, either absolutely, or in the Waterfront Commission’s discretion. No positions on the waterfront were more conducive to its criminal past than those of union officials, and none, if left unregulated, were felt to be more able to impede the waterfront’s reform. Duly mindful as we are of the promising record of rehabilitation by ex-felons, and of the emphasis on rehabilitation by modern penological efforts, it is not for this Court to substitute its judgment for that of Congress and the Legislatures of New York and New Jersey regarding the social surgery required by a situation as gangrenous as exposure of the New York waterfront had revealed.
Barring convicted felons from certain employments is a familiar legislative device to insure against corruption in [159]*159specified, vital areas. Federal law has frequently and of old utilized this type of disqualification. Convicted felons are not entitled to be enlisted or mustered into the United States Army, or into the Air Force, but “the Secretary . . . may authorize exceptions, in meritorious cases.” 10 U. S. C. §§ 3253, 8253. This statute dates from 1833. A citizen is not competent to serve on federal grand or petit juries if he has been “convicted in a State or Federal court of record of a crime punishable by imprisonment for more than one year and and [sic] his civil rights have not been restored by pardon or amnesty.” 28 U. S. C. § 1861. In addition, a large group of federal statutes disqualify persons “from holding any office of honor, trust, or profit under the United States” because of their conviction of certain crimes, generally involving official misconduct. 18 U. S. C. §§ 202, 205, 206, 207, 216, 281, 282, 592, 1901, 2071, 2381. For other examples in the federal statutes see 18 U. S. C. § 2387; 5 U. S. C. § 2282; 8 U. S. C. § 1481. State provisions disqualifying convicted felons from certain employments important to the public interest also have a long history. See, e. g., Hawker v. New York, 170 U. S. 189. And it is to be noted that in § 504 (a) of the 1959 Federal Labor Act, qu.oted earlier in this opinion, Congress adopted this same solution in its attempt to rid all unions of criminal elements. Just as New York and New Jersey have done, the 1959 Federal Act makes a prior felony conviction a bar to union office unless there is a favorable exercise of executive discretion. In the face of this wide utilization of disqualification of convicted felons for certain employments closely touching the public interest, remitting them to executive discretion to have the bar removed, we cannot say that it was not open to New York to clean up its waterfront in the way it has. New York was not guessing or indulging in airy assumptions that convicted felons constituted a deleterious influence on the waterfront. It was acting on impressive [160]*160if mortifying evidence that the presence on the waterfront of ex-convicts was an important contributing factor to the corrupt waterfront situation.
Finally, § 8 of the Waterfront Commission Act is neither a bill of attainder nor an ex post facto law. The distinguishing feature of a bill of attainder is the substitution of a legislative for a judicial determination of guilt. See United States v. Lovett, 328 U. S. 303. Clearly, § 8 embodies no further implications of appellant’s guilt than are contained in his 1920 judicial conviction; and so it manifestly is not a bill of attainder. The mark of an ex post facto law is the imposition of what can fairly be designated punishment for past acts. The question in each case where unpleasant consequences are brought to bear upon an individual for prior conduct, is whether the legislative aim was to punish that individual for past activity, or whether the restriction of the individual comes about as a relevant incident to a regulation of a present situation, such as the proper qualifications for a profession. See Hawker v. New York, 170 U. S. 189. No doubt is justified regarding the legislative purpose of § 8. The proof is overwhelming that New York sought not to punish ex-felons, but to devise what was felt to be a much-needed scheme of regulation of the waterfront, and for the effectuation of that scheme it became important whether individuals had previously been convicted of a felony.
Affirmed.
Mr. Justice Harlan took no part in the consideration or decision of this case.
Mr. Justice Brennan
is of opinion that Congress has demonstrated its intent that § 8 of the New York Waterfront Commission Act should stand despite the provisions of the National Labor Relations Act, and that the Labor-Management Reporting and Disclosure Act of [161]*1611959 explicitly provides that it shall not displace such legislation of the States. He believes that New York’s disqualification of ex-felons from waterfront union office, on all the circumstances, and as applied to this specific area, is a reasonable means for achieving a legitimate state aim, and does not deny due process or otherwise violate the Federal Constitution. Accordingly, he agrees that the judgment should be affirmed.