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. Doe 2 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.