delivered the opinion of the Court.

We granted certiorari to consider petitioner’s claim that the provisions of Title II of the Narcotic Addict Rehabilitation Act of 1966, 18 U. S. C. §§ 4251-4255, deny due process and equal protection by excluding from discretionary rehabilitative commitment, in lieu of penal incarceration, addicts with two or more prior felony convictions. The Circuits are in apparent conflict on this question. See the opinion of the Court of Appeals in this case, sub nom. Marshall v. Parker, 470 F. 2d 34 (CA9), and Watson v. United States, 141 U. S. App. D. C. 335, 439 F. 2d 442 (1970); United States v. Hamilton, 149 U. S. App. D. C. 295, 462 F. 2d 1190 (1972); United States v. Bishop, 469 F. 2d 1337 (CA1 1972); and Macias v. United States, 464 F. 2d 1292 (CA5 1972), cert. pending, No. 72-5539.

(1)

Petitioner, Robert Edward Marshall, pleaded guilty to an indictment charging him with entering a bank with intent to commit a felony, in violation of 18 U. S. C. § 2113 (a). At sentencing, petitioner requested that he be considered for treatment as a narcotic addict pursuant to Tit. II of the Narcotic Addict Rehabilitation Act of *4191966 (NARA). The sentencing judge, after noting petitioner’s prior felony convictions for burglary, forgery, and possession of a firearm, concluded that the exclusion of persons with two prior convictions from the discretionary provisions of the Act as set forth in 18 U. S. C. § 4251 (f) (4)1 did not permit commitment under *420NARA. Petitioner was sentenced to 10 years’ imprisonment pursuant to 18 U. S. C. §4208 (a)(2), but the District Judge recommended that petitioner receive treatment for narcotics addiction while incarcerated.2

Ten months after being sentenced, petitioner moved to vacate his sentence under 28 U. S. C. § 2255 on the ground that the two-prior-felony exclusion of NARA under § 4251 (f) (4) violates equal protection as embodied in the Due Process Clause of the Fifth Amendment.

The District Judge took note of Watson v. United States, supra, but declined to follow that holding. The District Judge also noted that there was no showing, as in Watson, supra, that petitioner’s prior convictions and his drug addiction were related 3 and since his prior convictions did not relate to traffic in narcotics, the provisions *421of 18 U. S. C. § 4251 (f) (2) did not apply. The District Judge determined that, given the purposes of the statute, Congress had not acted arbitrarily in providing different disposition standards for convicted persons with records of prior felony convictions from those without such convictions, these classifications being related to eligibility for rehabilitative commitment under NARA.

The Court of Appeals viewed petitioner’s § 2255 petition as a motion under Rule 35 of the Federal Rules of Criminal Procedure for correction of an illegal sentence, and held the statutory classification constitutionally permissible, noting its disagreement with the decisions in Watson, supra, and United States v. Hamilton, supra. Viewing the Act in its entirety,4 the Court of Appeals concluded that Congress expressly limited the reach of the Act to addicts most likely to be rehabilitated through treatment and provided an exclusion as to convicted persons having two or more prior convictions.

Concluding there is no “fundamental right” to rehabilitation from narcotics addiction at public expense after conviction of a crime, and there being no “suspect” classification under the statutory scheme, the Court of Appeals considered the correct standard to be whether the statu*422tory classification bore “some relevance to the purpose for which the classification is made.” Baxstrom v. Herold, 383 U. S. 107, 111 (1966); Dandridge v. Williams, 397 U. S. 471 (1970). The court reasoned that Congress adopted the challenged standards in an effort to restrict eligibility to those most likely to respond to treatment and held that Congress could not be said to have acted irrationally in so doing. The District Court's denial of petitioner’s motion to vacate his sentence was affirmed, 470 F. 2d 34 (CA9 1972). We granted certiorari, 410 U. S. 954 (1973). We agree with the District Court’s and the Court of Appeals’ reading of the statute and affirm.

(2)

Petitioner concedes that the concept of equal protection as embodied in the Due Process Clause of the Fifth Amendment, see Bolling v. Sharpe, 347 U. S. 497 (1954), does not require that all persons be dealt with identically, but rather that there be some “rational basis” for the statutory distinctions made, McGinnis v. Royster, 410 U. S. 263, 270 (1973), or that they “have some relevance to the purpose for which the classification is made.” Baxstrom v. Herold, supra, at 111; Rinaldi v. Yeager, 384 U. S. 305, 309 (1966). See also James v. Strange, 407 U. S. 128 (1972); Humphrey v. Cady, 405 U. S. 504 (1972). He argues that no such nexus exists under the classification provided by the challenged statute.

The broad purpose of Congress in enacting NARA, as set forth in the Act itself, was:

“[T]hat certain persons charged with or convicted of violating Federal criminal laws, who are determined to be addicted to narcotic drugs, and likely to be rehabilitated through treatment, should, in lieu of prosecution or sentencing, be civilly committed for confinement and treatment designed to *423effect their restoration to health, and return to society as useful members.” 42 U. S. C. § 3401.

See also H. R. Rep. No. 1486, 89th Cong., 2d Sess., 7 (1966), (“to provide for the treatment and rehabilitation of narcotic addicts when they are charged with or convicted of offenses against the United States”); S. Rep. No. 1667, 89th Cong., 2d Sess., 12 (1966). Congress recognized that some relationship between drug addiction and crime probably existed, and concluded that prosecution and imprisonment of all addicts, without more, would not cure addiction or retard the rising addiction rate, and that a rehabilitative rather than a purely penal aproach to the problem was called for. Id., at 13, 17.

It was not the purpose of Congress, however, to make every addict eligible for civil commitment simply by reason of addiction. The congressional intent in adopting the statutory exclusion based on prior convictions which is challenged here is somewhat less explicitly defined,5 but the objectives emerge clearly when the Act is read as a whole. Having recognized some nexus between drug addiction and crime, Congress specifically sought to insure that any program aimed at providing for the treatment of drug addiction wpuld not hinder *424traditional efforts to deal effectively with the strictly criminal aspects of the problem.6 The most explicit statement of congressional intent is found in the House Report:

“The practical effect of the implementation of the law provided for in the bill, is that strict punishment can be meted out where required to the hardened criminal, while justice can be tempered with judgment and fairness in those cases where it is to the best interest of society and the individual that such ■ a course be followed.

“The definition of ‘eligible individuar as set forth in the bill insures that the persons considered as candidates for civil commitment will not include criminals charged with violent crimes or be those whose records disclose a history of serious crimes.” 7 H. R. Rep. No. 1486, pp. 9-10. (Emphasis supplied.)

Similarly, the Senate Report notes:

“The bill contains sufficient safeguards to assure adequate protection of the general public against the addict who is or may be a hardened criminal, while providing the flexibility necessary to enable *425Federal authorities to medically treat the addict who is capable of being cured and rehabilitated ....” S. Rep. No. 1667, p. 13.8

It is quite clear that in adopting the two-prior-felony exclusion, Congress sought first, to exclude from NARA treatment those less likely to be rehabilitated by such treatment, and second, to exclude those whose records disclosed a “history of serious crimes.” The question we are called upon to decide is whether Congress could rationally have assumed that a person who has committed two or more prior felonies and is an. addict at the time sentence is to be imposed is likely to be less susceptible of rehabilitation by reason of his past record, thus posing a greater threat to society upon release.

Congress’ concern with susceptibility and suitability of multiple offenders to rehabilitative treatment can reasonably be said to derive from its belief that because of the nature of addiction treatment, one who had evidenced greater difficulty in conforming his behavior to societal rules and laws would himself be less likely to benefit from treatment. Additionally, such a person might also pose impediments to the successful treatment of others in the program. As testimony before both the House and *426Senate committees revealed, the treatment process for narcotics addiction is an arduous and a delicate undertaking, particularly in the aftercare stage when the subject is released into an unstructured environment which requires from the addict strict obedience to the limitations of the prescribed regime and full cooperation in the rehabilitative efforts.9

*425The bill which emerged from conference included the two-prior-felony exclusion, and the report on that bill merely noted that “the conferees for the Senate felt it reasonable to exclude hardened offenders with serious criminal records and persons who have demonstrated their unsuitability for civil treatment.” 112 Cong. Rec. 27616 (1966).

*426Additionally, there is no generally accepted medical view as to the efficacy of presently known therapeutic methods of treating addicts and the prospect for the successful rehabilitation of narcotics addicts thus remains shrouded in uncertainty. Indeed, even the premise that drug addiction is one of the significant root causes of crime is not without challenge. See generally D. Musto, The American Disease: Origins of Narcotic Control (1973). See also American Bar Association and American Medical Association, Joint Committee on Narcotic Drugs, Drug Addiction: Crime or Disease? (1961). As testimony before the Congress revealed, no evidence to date has demonstrated more than a speculative chance for the successful rehabilitation of narcotics addicts. H. R. Rep. No. 1486, at 51. S. Rep. No. 1667, at 14. The NARA program was therefore fundamentally experimental in nature. See 112 Cong. Rec. 11896-11901 (1966). The suggestion that there is “obscurity” in the holding of this Court in Powell v. Texas, 392 U. S. 514 (1968), fails to take into account that when courts deal with problems in the administration of criminal law such as those related to drug addiction, alcoholism, *427mental disease, and the like, they are necessarily confined to the existing limits of human knowledge in those areas. As Mr. Justice Marshall noted in Powell:

“[T]he inescapable fact is that there is no agreement among members of the medical profession about what it means to say that ‘alcoholism' is a ‘disease.’ One of the principal works in this field states that . . . ‘alcoholism has too many definitions and disease has practically none.’ ” Id., at 522.

The holding in Powell was a candid acknowledgment that the medical uncertainties afford little basis for judicial responses in absolute terms.

When Congress undertakes to act in areas fraught with medical and scientific uncertainties, legislative options must be especially broad and courts should be cautious not to rewrite legislation, even assuming, arguendo, that judges with more direct exposure to the problem might make wiser choices. Accordingly, it would have been a permissible choice for Congress to permit discretionary inclusion in NARA programs of those whose prior offenses were determined to be addiction related or motivated. Such a discretion might appropriately have been vested in the trial judge much in the manner in which he is now required to exercise his discretion under § 4252 in determining whether the defendant is an addict who is likely to be rehabilitated through treatment.10 That Congress has not yet chosen to so provide, however, does not render constitutionally impermissible its decision to limit treatment to those with less than two prior felony convictions. Williamson v. Lee Optical Co., 348 U. S. 483 (1955); Dandridge v. *428Williams, 397 U. S. 471 (1970); McGowan v. Maryland, 366 U. S. 420 (1961); Jefferson v. Hackney, 406 U. S. 535 (1972).

It should be recognized that the classification selected by Congress is not one which is directed “against” any individual or category of persons, but rather it represents a policy choice in an experimental program made by that branch of Government vested with the power to make such choices. The Court has frequently noted that legislative classifications need not be perfect or ideal. The line drawn by Congress at two felonies, for example, might, with as much soundness, have been drawn instead at one, but this was for legislative, not judicial choice. McGinnis v. Royster, 410 U. S. 263 (1973); Powell v. Texas, supra, at 539-540 (Black, J., concurring). Against this background, it cannot be said that it was unreasonable or irrational for Congress to act on the predicate reflected in the legislative history and explicitly stated in the exclusion provision of § 4251 (f)(4), that a person with tvfo or more prior felonies would be less likely to adjust and adhere to the disciplines and rigors of the treatment program11 and hence is a less promising prospect for treatment than those with lesser criminal records.

In addition, Congress might rationally have sought to exclude from NARA treatment centers those it thought might be potentially disruptive elements within the sensitive environment of a drug treatment program.12 Nor *429can Congress be said to have acted without reason in determining that an addict with multiple convictions was more “hardened” and thus a greater potential danger to society on early release than the addict who had committed one prior felony or none.

Under NARA, Congress provided for comparatively lenient sentencing possibilities,13 but in excluding addicts with two prior felonies, it sought to assure that in an essentially experimental program to which limited resources were allocated these features would not be exploited by persons who were viewed by Congress as primarily antisocial and only secondarily addicts.14 In addition, since the fact of two prior felony convictions may be said to evidence a lesser susceptibility of de*430terrence, the reduced level of deterrence implicit in the benign policy of Title II could reasonably be thought by Congress to create an unacceptable risk to society and thus require the exclusion of such persons from NARA disposition.

We therefore hold that Title II of NARA, 18 U. S. C. §§ 4251-4255, does not constitute a denial of due process or equal protection by excluding from rehabilitative commitment, in lieu of penal incarceration, addicts with two or more prior felony convictions.

Affirmed.

with whom Mr. Justice Douglas and Mr. Justice Brennan concur, dissenting.

Title II of the Narcotic Addict Rehabilitation Act of 1966 authorizes treatment in lieu of prison sentence for those addicts convicted of an offense against the United States who the sentencing court has determined are “likely to be rehabilitated through treatment." 18 U. S. C. §4253 (a). Petitioner was denied treatment for his disease of narcotics addiction, even though no determination was ever made that he is not likely to be rehabilitated through treatment, because the Act excludes from consideration for the NARA program any person with two or more prior felony convictions. 18 U. S. C. §4251 (f)(4). Two courts of appeals have concluded that the two-felony exclusion, though intended by Congress to serve admittedly legitimate ends, is not a sufficiently rational means toward those ends to withstand scrutiny under equal protection principles.1 *431The Court today, while alluding to some of the statute’s serious flaws, nevertheless finds it constitutional. I must respectfully dissent.

In the present case the Court of Appeals analyzed the constitutionality of the two-felony exclusion by focusing on what it perceived to be this Court’s two-tiered approach to equal protection issues. See 470 F. 2d 34, 38 (1972). Under this view, classifications involving a “fundamental interest” or “suspect classification” are subject to so-called “strict scrutiny,” while all other statutes are tested by a standard of minimal rationality. While the Court today neither expressly endorses nor rejects this approach, its analysis is so deferential as to confirm an earlier observation that, except in cases where the Court chooses to invoke strict scrutiny, the Equal Protection Clause has been all but emasculated. See *432San Antonio School Dist. v. Rodriguez, 411 U. S. 1, 98 (Marshall, J., dissenting).2

At the outset, then, I must once again take issue with the Court’s apparently rigid approach to equal protection issues. See, e. g., Dandridge v. Williams, 397 U. S. 471, 519-530 (1970) (Marshall, J., dissenting); Richardson v. Belcher, 404 U. S. 78, 90-91 (1971) (Marshall, J., dissenting); San Antonio School Dist. v. Rodriguez, supra, at 98-110 (Marshall, J., dissenting). True, as the Court of Appeals found, this case does not fit into any neat “fundamental interest” or “suspect classification” mold. Notwithstanding, I find it hard to understand why a statute which sends a man to prison and deprives him of the opportunity even to be considered for treatment for his disease of narcotics addiction,3 while *433providing treatment and suspension of prison sentence to others similarly situated, should be tested under the same minimal standards of rationality that we apply to statutes regulating who can sell eyeglasses or who can own pharmacies. See Williamson v. Lee Optical Co., 348 U. S. 483 (1955); North Dakota State Bd. of Pharmacy v. Snyder’s Drug Stores, Inc., ante, p. 156. This case does not involve discrimination ■ against business interests more than powerful enough to protect themselves in the legislative halls, but the very life and health of a man caught up in the spiraling web of addiction and crime.

I press my disagreement no further here, for a careful analysis of the two-felony exclusion and the ends Congress sought to achieve shows that the exclusion is a totally irrational means toward those ends. If deferential scrutiny under the equal protection guarantee is to mean more than total deference and no scrutiny, surely it must reach the statutory exclusion involved in this case.

One of Congress’ primary purposes in enacting the two-felony exclusion was to limit treatment to those convicted persons considered most deserving of the special benefits provided by the new law. As the Government argues in its brief, Congress wanted to grant the benefits of treatment to those who “were primarily addicts, and only secondarily criminals.” Brief for United States 6. To state the goal more precisely, Congress intended to give treatment to those addicts whose criminal activity was only a symptom or product of their addiction. The *434House Report recognized that “Narcotic addicts in their desperation to obtain drugs often turn to crime in order to obtain money to feed their addiction.” H. R. Rep. No. I486, 89th Cong., 2d Sess., 8 (1966). On the other hand, Congress knew there were others who were first of all criminals, and only secondarily addicts — that is, persons whose criminal activity was independent of their narcotics addiction. It was thought important to preserve strict criminal penalties for such hardened criminals, rather than permit them to use the fact of their addiction to escape punishment for a crime. See 112 Cong. Rec. 11813 (1966).

The plain fact of the matter, however, is that the two-felony exclusion does not further this legislative end, as the following examples demonstrate. Defendant A, with a prior felony conviction for assault with intent to commit murder, is convicted of stealing funds from a national bank. Neither crime was in any way related to narcotics addiction. In fact, A was not even an addict at the time he committed the crimes, but has become an addict during the pendency of his bank theft trial. Defendant B, who has two prior felony convictions for narcotics offenses, is convicted of possession of heroin for his own use. Given the above-stated legislative purpose, one would think that Defendant B, all of whose criminal activity was related to his narcotics addiction, would be eligible for NARA treatment, while Defendant A, none of whose criminal activity was so related, would not be eligible. But just the opposite is true, because of the two-felony exclusion.4

*435The problem with the statute is not, as the majority would have it, that Congress chose two felonies as the cutoff point rather than one or three. Rather, the statute fails to achieve the legislative end of discriminating between people who are mainly addicts and those who are mainly criminals because a numerical test was used to achieve a qualitative result for which it was totally unsuited.

A second basic purpose sought to be achieved through the two-felony exclusion was to restrict NARA treatment to those persons deemed likely to be rehabilitated. But the two-felony rule, again, is not a rational means toward that end. To begin with, it must be remembered that the statute itself limits participation in the program to those persons who, after an examination in the custody of the Attorney General, are determined to be addicts “likely to be rehabilitated through treatment.” The two-felony exclusion, to the extent it is justified by reference to this policy, amounts to a conclusive and irrebuttable presumption that a person with two or more felony convictions is not likely to be rehabilitated through treatment. We have only recently reiterated that “permanent irrebuttable presumptions have long been disfavored,” see Vlandis v. Kline, 412 U. S. 441, 446 (1973). This is particularly true where an interest as important as personal liberty is at stake. And as one would expect of medical problems in general, whether a particular individual’s disease of narcotics addiction is amenable to treatment is the very kind of question which requires an individualized determination.5

*436The two-felony presumption of nonamenability to rehabilitation is also plainly contrary to fact. The Administrator of the California Youth and Adult Corrections Agency pointed out that the two-or-more-felony provision “would result in a great many persons being excluded who might prove to be the best subjects for the program.” 6 As he indicated, it was the experience of the California program,7 upon which the federal program was modeled in large part, that “persons who have had as many as four or five previous convictions and have grown older in years respond to the program better than some of the younger persons earlier in their careers.” 8 Nor was any contrary evidence presented to Congress.

Another purpose of the two-felony exclusion was to weed out those violent, antisocial individuals whose *437participation in the program would interfere with the rehabilitation of others. But again, Congress has drawn a numerical test to achieve a qualitative result for which it is manifestly unsuited. An addict with a prior conviction for attempted murder can participate in the NARA program, while one whose prior record includes two convictions for possession of narcotic drugs cannot.9

It makes no sense to deem an addict a “hardened criminal” unworthy or unsuited for treatment simply because he has engaged in criminal activity which may have been the symptom or product of his addiction. Congress enacted NARA because it knew that almost all addicts are hardened criminals in this sense. Not only are they driven to rob and steal in order to obtain money to sustain their habits, but their habits themselves involve the commission of felonies every day of their lives. As the House Report stated, the purpose of the bill was “to treat the unfortunate addict who is capable of rehabilitation ..to render assistance in a manner which will enable him to extricate himself from an otherwise hopeless and repetitious pattern of addiction and crime.” 10 To deny treatment to those addicts who have been convicted of a certain number of felonies, without regard to the relationship between their addiction and the prior offenses, is, in the *438apt words of Congressman Ryan, like “building a sanatorium to treat tuberculosis, and then refusing admittance to patients with a contagious disease.” 112 Cong. Rec. 11812 (1966).11

It is argued that the NARA program is essentially experimental in nature, and that courts should therefore be particularly reluctant to interfere with legislative decisions. But this observation must be tempered by a realization that we are experimenting here with people’s lives and health. And it can hardly be said that a program now in its seventh year of operation is still basically experimental. Only last year, Congress broadened the NARA program to include methadone maintenance as part of the available rehabilitative treatment, recognizing the many cases of addiction which, though *439not totally curable, can be maintained in a manner which fosters the individual’s social rehabilitation and permits him to become a productive member of society. See Pub. L. No. 92-420, 86 Stat. 677; S. Rep. No. 92-1071 (1972). With the program widened in this fashion, it seems even more irrational to exclude those who might well benefit from the expanded program through the operation of broad and arbitrary exclusions that do not reasonably further any legitimate congressional purposes.

Finally, we must be mindful that the growing concern with treatment of narcotics addicts has not arisen in a legal vacuum, but has paralleled a growing awareness of the Eighth Amendment questions raised when criminal punishment is imposed for activities which are the symptom or direct product of the disease of narcotics addiction.12 The Court today, by dicta implying that Congress may, consistent with the equal protection concept, deny NARA benefits to persons convicted of narcotics-related offenses because of two prior convictions *440for narcotics-related offenses,13 only exacerbates these Eighth Amendment problems.

Mr. Justice Jackson, himself a strong opponent of substantive due process, once argued that the vitality of the Equal Protection Clause as a ground for constitutional adjudication is that it “does not disable any governmental body from dealing with the subject at hand.” Rather, it merely sends the legislature back to the drawing board to draft a statute which more precisely and more evenhandedly solves the problem. See Railway Express v. New York, 336 U. S. 106, 112 (1949) (concurring opinion). I would not deny Congress the right to limit the NARA program to persons whose criminal activity was a product of their addiction, to those who were likely to be rehabilitated, or to those whose presence in a treatment center would not interfere with the rehabilitation of others. But I would have Congress make a second attempt at drafting a statute which actually furthers these ends.