[Rich Z]

Does anyone know if the Florida Constitution prohibits ex post facto laws? The US Constitution certainly does, and I thought most state constitutions are based on the federal version.

An ex post facto law (from the Latin for "from something done afterward") or retroactive law, is a law that retroactively changes the legal consequences of acts committed or the legal status of facts and relationships that existed prior to the enactment of the law. In reference to criminal law, it may criminalize actions that were legal when committed; or it may aggravate a crime by bringing it into a more severe category than it was in at the time it was committed; or it may change or increase the punishment prescribed for a crime, such as by adding new penalties or extending terms; or it may alter the rules of evidence in order to make conviction for a crime more likely than it would have been at the time of the action for which a defendant is prosecuted. Conversely, an ex post facto law, commonly known as an amnesty law, may decriminalize certain acts or alleviate possible punishments (for example by replacing the death sentence with life-long imprisonment) retroactively.

A law may have an ex post facto effect without being technically ex post facto. For example, when a law repeals a previous law, the repealed legislation no longer applies to the situations it once did, even if such situations arose before the law was repealed. The principle of prohibiting the continued application of these kinds of laws is also known as Nullum crimen, nulla poena sine praevia lege poenali.

Generally speaking, ex post facto laws are seen as a violation of the rule of law as it applies in a free and democratic society. Most common law jurisdictions do not permit retroactive legislation, though some have suggested that judge-made law is retroactive as a new precedent applies to events that occurred prior to the judicial decision. In some nations that follow the Westminster system of government, such as the United Kingdom, ex post facto laws are technically possible as parliamentary supremacy allows the parliament to pass any law it wishes. However, in a nation with an entrenched bill of rights or a written constitution, ex post facto legislation may be prohibited.