4. Ex Post Facto Law

Ex Post Facto Law

General Rule: A felony shall be punishable only by the penalty prescribed by law at the time of its commission.

Art. 21 implements the constitutional prohibition against ex post facto laws. It reflects the maxim that there is no crime without law and that there is no penalty without law (nullum crimen sine lege; nulla poena sine lege).

An ex post facto law is one which:

• Makes criminal an act done before the passage of the law and which was innocent when done, and punishes such an act;
• Aggravates a crime, or makes it greater than it was, when committed;
• Changes the punishment and inflicts a greater punishment than the law annexed to the crime when committed;
• Alters the legal rules of evidence, and authorizes conviction upon less or different testimony than the law required at the time of the commission of the offense;
• Assuming to regulate civil rights and remedies only, in effect imposes penalty or deprivation of a right for something which when done was lawful; and
• Deprives a person accused of a crime of some lawful protection to which he has become entitled, such as the protection of a former conviction or acquittal, or a proclamation of amnesty. (Mejia vs. Pamaran, G.R. Nos. L56741-42)