3. Prospectivity

Prospectivity

Concept

Prospectivity asks which criminal law governs conduct when the law changes over time. The starting point is that criminal responsibility must rest on a law applicable when the conduct took place. The Constitution prohibits the enactment of an ex post facto law, while the Rome Statute expressly addresses both the time of the conduct and changes in applicable law before final judgment. (Art. III, Sec. 22, 1987 Const.)¹ (Art. 22, Rome Statute)² (Art. 24, Rome Statute)³

Governing provisions

• Constitution: Article III, Section 22 prohibits the enactment of an ex post facto law or bill of attainder. (Art. III, Sec. 22, 1987 Const.)¹
• Rome Statute, Article 22: Responsibility under the Statute requires that the conduct constituted a crime within the Court’s jurisdiction when it occurred. Crime definitions must be strictly construed, without extension by analogy; ambiguity favors the person investigated, prosecuted, or convicted. (Art. 22, Rome Statute)²
• Rome Statute, Articles 23 and 24: Punishment by the Court must accord with the Statute. The Statute excludes criminal responsibility for conduct before its entry into force and directs the use of the more favorable applicable law when the law changes before final judgment. (Art. 23, Rome Statute)⁴ (Art. 24, Rome Statute)³

Requisites / Rules

• Identify when the alleged conduct occurred and whether it was already a crime under the law invoked. Under Article 22 of the Rome Statute, a crime definition cannot be enlarged by analogy to establish responsibility under that Statute. (Art. 22, Rome Statute)²
• If the applicable law changed, determine whether the change favors the accused. In a Philippine case, the Court applied a new substantive law retroactively because it removed an essential element of the charged offense, subject to the stated condition that the accused was not a habitual criminal. (Morgado v. People of the Philippines, G.R. No. 271081, 29 July 2024)⁵

Distinctions

Do not confuse the prohibition against an ex post facto law with a favorable change in penal law. The first is a constitutional prohibition; the latter may benefit the accused. In the cited Philippine case, removal of the election-period element meant that the accused could not be convicted of the charged election offense. (Art. III, Sec. 22, 1987 Const.)¹ (Morgado v. People)⁵

Key doctrines

A conviction requires proof beyond reasonable doubt both in fact and in law. Courts must not distort plain statutory provisions to favor punishment. Where the new substantive law eliminated an essential element of the offense and the favorable-retroactivity rule applied, the Court acquitted the accused. (Morgado v. People)⁵

Exceptions

The Rome Statute’s rule on crimes within the Court’s jurisdiction does not affect the characterization of conduct as criminal under international law independently of that Statute. Its more-favorable-law provision addresses a change in applicable law before final judgment. (Art. 22, Rome Statute)² (Art. 24, Rome Statute)³

Bar tip

Fix the date of the conduct, identify the law then applicable, and check whether a later change removes an element or otherwise favors the accused. Keep the constitutional rule, the Philippine case doctrine, and the Rome Statute’s rules in their proper contexts. (Art. III, Sec. 22, 1987 Const.)¹ (Morgado v. People)⁵ (Art. 24, Rome Statute)³