ArtI.S10.C1.5.1 Scope of the Provision

Article I, Section 10, Clause 1:

No State shall enter into any Treaty, Alliance, or Confederation; grant Letters of Marque and Reprisal; coin Money; emit Bills of Credit; make any Thing but gold and silver Coin a Tender in Payment of Debts; pass any Bill of Attainder, ex post facto Law, or Law impairing the Obligation of Contracts, or grant any Title of Nobility.

The prohibition against state ex post facto laws, like the cognate restriction imposed on the Federal Government by § 9, relates only to penal and criminal legislation and not to civil laws that affect private rights adversely. 1 Distinguishing between civil and penal laws was at the heart of the Court’s decision in Smith v. Doe2 upholding application of Alaska’s Megan’s Law to sex offenders who were convicted before the law’s enactment. The Alaska law requires released sex offenders to register with local police and also provides for public notification via the Internet. The Court accords considerable deference to legislative intent; if the legislature’s purpose was to enact a civil regulatory scheme, then the law can be ex post facto only if there is the clearest proof of punitive effect. 3 Here, the Court determined, the legislative intent was civil and non-punitive – to promote public safety by protecting the public from sex offenders. The Court then identified several useful guideposts to aid analysis of whether a law intended to be non-punitive nonetheless has punitive effect. Registration and public notification of sex offenders are of recent origin, and are not viewed as a traditional means of punishment.4 The Act does not subject the registrants to an affirmative disability or restraint; there is no physical restraint or occupational disbarment, and there is no restraint or supervision of living conditions, as there can be under conditions of probation. The fact that the law might deter future crimes does not make it punitive. All that is required, the Court explained, is a rational connection to a non-punitive purpose, and the statute need not be narrowly tailored to that end. 5 Nor is the act “excessive” in relation to its regulatory purpose. 6 Rather, the means chosen are reasonable in light of the [state’s] non-punitive objective of promoting public safety by giving its citizens information about former sex offenders, who, as a group, have an alarmingly high rate of recidivism. 7

There are three categories of ex post facto laws: those which punish[ ] as a crime an act previously committed, which was innocent when done; which make[ ] more burdensome the punishment for a crime, after its commission; or which deprive[ ] one charged with crime of any defense available according to law at the time when the act was committed.8 The bar is directed only against legislative action and does not touch erroneous or inconsistent decisions by the courts. 9

The fact that a law is ex post facto and invalid as to crimes committed prior to its enactment does not affect its validity as to subsequent offenses. 10 A statute that mitigates the rigor of the law in force at the time the crime was committed, 11 or merely penalizes the continuance of conduct lawfully begun before its passage, is not ex post facto. Thus, measures penalizing the failure of a railroad to cut drains through existing embankments 12 or making illegal the continued possession of intoxicating liquors which were lawfully acquired 13 have been held valid.


  1.  Jump to essay-1Calder v. Bull, 3 U.S. (3 Dall.) 386, 390 (1798); Watson v. Mercer, 33 U.S. (8 Pet.) 88, 110 (1834); Baltimore and Susquehanna R.R. v. Nesbit, 51 U.S. (10 How.) 395, 401 (1850); Carpenter v. Pennsylvania, 58 U.S. (17 How.) 456, 463 (1855); Loche v. New Orleans, 71 U.S. (4 Wall.) 172 (1867); Orr v. Gilman, 183 U.S. 278, 285 (1902); Kentucky Union Co. v. Kentucky, 219 U.S. 140 (1911). In Eastern Enterprises v. Apfel, 524 U.S. 498, 538 (1998) (concurring), Justice Thomas indicated a willingness to reconsider Calder to determine whether the clause should apply to civil legislation.
  2.  Jump to essay-2538 U.S. 84 (2003).
  3.  Jump to essay-3538 U.S. at 92.
  4.  Jump to essay-4The law’s requirements do not closely resemble punishments of public disgrace imposed in colonial times; the stigma of Megan’s Law results not from public shaming but from the dissemination of information about a criminal record, most of which is already public. 538 U.S. at 98.
  5.  Jump to essay-5538 U.S. at 102.
  6.  Jump to essay-6Excessiveness was alleged to stem both from the law’s duration (15 years of notification by those convicted of less serious offenses; lifetime registration by serious offenders) and in terms of the widespread (Internet) distribution of the information.
  7.  Jump to essay-7538 U.S. at 105. Unlike involuntary civil commitment, where the magnitude of restraint [makes] individual assessment appropriate, the state may make reasonable categorical judgments, and need not provide individualized determinations of dangerousness. Id. at 103.
  8.  Jump to essay-8Collins v. Youngblood, 497 U.S. 37, 42 (1990) (quoting Beazell v. Ohio, 269 U.S. 167, 169-70 (1925)). Alternatively, the Court described the reach of the clause as extending to laws that alter the definition of crimes or increase the punishment for criminal acts. Id. at 43. Justice Chase’s oft-cited formulation has a fourth category: “every law that aggravates a crime, or makes it greater than it was, when committed.” Calder v. Bull, 3 U.S. (3 Dall.) 386, 390 (1798), cited in, e.g., Carmell v. Texas, 529 U.S. 513, 522 (2000).
  9.  Jump to essay-9Frank v. Mangum, 237 U.S. 309, 344 (1915); Ross v. Oregon, 227 U.S. 150, 161 (1913). However, an unforeseeable judicial enlargement of a criminal statute so as to encompass conduct not covered on the face of the statute operates like an ex post facto law if it is applied retroactively and violates due process in that event. Bouie v. City of Columbia, 378 U.S. 347 (1964). See Marks v. United States, 430 U.S. 188 (1977) (applying Bouie in context of § 9, cl. 3). But see Splawn v. California, 431 U.S. 595 (1977) (rejecting application of Bouie). The Court itself has not always adhered to this standard. See Ginzburg v. United States, 383 U.S. 463 (1966).
  10.  Jump to essay-10Jaehne v. New York, 128 U.S. 189, 194 (1888).
  11.  Jump to essay-11Rooney v. North Dakota, 196 U.S. 319, 325 (1905).
  12.  Jump to essay-12Chicago & Alton R.R. v. Tranbarger, 238 U.S. 67 (1915).
  13.  Jump to essay-13Samuels v. McCurdy, 267 U.S. 188 (1925).