Congress is prohibited from passing laws retrospectively, pursuant to Section 9 of the United States Constitution. States are prohibited from legislating retrospectively by tabling article 1, section 10, paragraph 1. This is one of the few restrictions that the U.S. Constitution placed on both federal and state government power prior to the Fourteenth Amendment. Thomas Jefferson described it as “equally unjust in civil and criminal cases.” Over the years, however, the U.S. Supreme Court has repeatedly relied on its decision in Calder v. Bull to rule on cases after the fact, in which Justice Samuel Chase concluded that the prohibition applied only to criminal cases and not to civil matters, and established four categories of unconstitutional retroactive laws. [39] The case concerned Article I, Section 10, prohibiting ex post facto legislation, since it was a law of the State of Connecticut. Australia does not have a strict constitutional prohibition on ex post facto laws, although narrowly retroactive laws may violate the constitutional principle of separation of powers.

Australian courts generally interpret laws with the strong presumption that they do not apply retroactively. The Convention also discussed whether the prohibition of retroactive legislation applies only to retroactive criminal statutes or whether it also prohibits retroactive civil law10FootnoteId. at 448–49, 617. Delegates rejected a proposal that would have amended the federal clause ex post to apply explicitly to civil law, but they did not clearly resolve the issue.11FootnoteId. at 617. See also id. to 440 (in view of an amendment to the state`s ex post facto clause that would have instead prohibited the enactment of retroactive laws). Shortly after ratification, in Calder v. Bull in 1798, the Supreme Court interpreted the constitutional prohibition of ex post facto laws as prohibiting only retroactive criminal laws.12Footnote3 U.S.

386, 389 (1798). See also 3 Joseph Story, Commentaries on the Constitution of the United States § 1339 (1833). Some laws are still passed retroactively: for example, the Pakistan Act 1990 (by which the United Kingdom amended its legislation after the Commonwealth of Nations readmitted Pakistan as a member) was such a law; Although adopted on 29 June 1990, Article 2(3) provides that `this Act shall be deemed to have entered into force on 1 October 1989`, that is to say, nine months before its entry into force. [34] The same section of Division XL subsequently prohibits criminal laws. As in France, there is an exception where retroactive criminal laws benefit the accused. Retroactive legislation pursuing what was considered a patently unethical means of tax avoidance was passed by the Fraser government in the early 1980s (see Down on Port Tax Avoidance). Similarly, a law retroactively criminalizing certain war crimes was declared constitutional (see Polyukhovich v. Commonwealth). The prohibition of state laws ex facto, like the related restriction imposed on the federal government by section 9, applies only to criminal and criminal laws, not to civil laws that infringe on private rights.2033 The distinction between civil and criminal law was at the heart of the Court`s decision in Smith v. Doe2034 maintains the application of Alaska`s “Megan`s Law” to sex offenders convicted before the law went into effect. Alaskan law requires released sex offenders to register with local police and also provides for public notification via the Internet. The Court of Justice pays “considerable attention” to the intention of the legislator; If Parliament`s purpose were to adopt a system of civil law regulation, the law can only apply ex post facto if there is “the clearest evidence” of the punitive effect.2035 In this case, according to the court, Parliament`s intent was civil, not punitive, – to promote public safety by “protecting the public from sex offenders.” The Court then identified several “useful benchmarks” to analyze whether a law that is not intended to be punitive nevertheless has a punitive effect.

The registration and public notification of sex offenders is of recent origin and is not considered a “traditional means of punishment”. 2036 The law does not subject registrants to “obstruction or positive restriction”; There is no physical restraint or occupational exclusion, and there is no restriction or monitoring of living conditions, as may be the case in probation conditions.