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Ex post facto law facts for kids

Kids Encyclopedia Facts

An ex post facto law (Latin for "after the fact" or "from after the action") is a law that changes the legal consequences (or status) of actions that were committed before the law went into effect. In criminal law, it may criminalize actions that were legal at the time they were committed. An ex post facto law may make a crime worse by bringing it into a more severe category than it was in when it was committed.

US Constitution

The United States Constitution prohibits ex post facto laws. Two clauses in the constitution prohibit ex post facto. Article 1 Section 9 of the U.S. Constitution states: 'No Bill of Attainder or ex post facto Law shall be passed,'. Section 10 says: '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. . .'

In civil law

Ex post facto laws relate only to criminal laws passed by legislations. It does not apply to civil laws "that affect private rights adversely." In 2003 the US Supreme court noted the difference between civil and penal laws.


The European Parliament prohibits ex post facto legislation by all member nations. They determined "Ex post facto legislation may also violate citizens’ right to effective legal redress and a fair trial..."

In English law, ex post facto laws are very rare. One example was the War Crimes Act 1991 by the Parliament of England. It allowed British citizens to be put on trial for war crimes that took place during World War II.

See also

Kids robot.svg In Spanish: Ley ex post facto para niños

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