Ex post facto, pronounced ɛks ˈpɒst ˈfæktəʊ, refers to a law or rule that applies retroactively to actions or situations that occurred before its enactment. The spelling of this Latin phrase is based on its pronunciation in English. The first word "ex" is pronounced as "eks," while "post" is pronounced as "pohst". The last two words "facto" are pronounced as "fakt-oh." The hyphen is often omitted, and the phrase is commonly spelled as "ex post facto."
Ex post facto is a Latin term that translates to "from a thing done afterward." In legal contexts, it refers to a law or action that has retroactive effect, altering the legal consequences of actions committed before the enactment of that law. It is a principle that prohibits the imposition of criminal penalties or punishment for an act that was not expressly criminalized at the time it was performed. Essentially, ex post facto laws cannot be applied to punish someone for conduct that was innocent or lawful when it occurred.
The concept of ex post facto is rooted in the principle of fairness and the protection of individuals from arbitrary or unjust laws. It serves as a safeguard against the government's ability to punish individuals for actions that were not considered illegal at the time of their occurrence. By prohibiting ex post facto laws, legal systems aim to uphold the fundamental principles of due process and non-retroactivity.
Furthermore, ex post facto can also pertain to situations where a law or regulation has a retroactive impact on contractual obligations, civil rights, or property rights. In such cases, it ensures that individuals are not deprived of their rights or subjected to changes that impair their legal or economic position. Ex post facto laws are generally considered unconstitutional in many jurisdictions, as they are seen as a violation of fundamental legal principles and the protection of individual rights.