Application of the Principle of Legality

The principle of legality is applied in various aspects of criminal law, including:

  • Investigation: Investigators can only carry out investigations into an act that is regulated as a criminal act in the law.
  • Prosecution: Public prosecutors can only prosecute someone in court if their actions are regulated as a criminal act in the law.
  • Examination in court: Judges can only decide cases based on applicable laws.

Principle of Legality and Principle of Lex Posterior

The principle of legality is closely related to the principle of lex posterior which states that the applicable law is the most recent law. If there is a change in the law after an act is committed, then the principle of lex favorabilior applies, which means that the law that is most favorable to the defendant is applied.

Challenges and Implementation of the Principle of Legality

Although the principle of legality is a fundamental principle, there are still several challenges in its implementation, including:

  • Unclear formulation of laws: Imprecise formulation of laws can lead to multiple interpretations and open opportunities for arbitrariness.
  • Rapid technological developments: Rapid technological developments can give rise to new types of criminal acts that are not yet regulated in the law.

Therefore, continuous efforts are needed to improve the quality of legislation and strengthen the implementation of the principle of legality in the Indonesian criminal justice system.Thus, the principle of legality can truly become the foundation of justice and legal certainty for the entire community.