Classic Debate: Formal vs. Material Theory

One of the most protracted academic discourses related to this principle is interpreting the phrase "changes in legislation". Criminal law experts are divided into several views:

  1. Formal (Narrow) Theory: Figures such as van Geuns argue that changes should be interpreted literally as changes to the wording of the criminal law itself. Changes to implementing regulations or factual situations do not trigger the application of Article 1 paragraph (2) of the Criminal Code.
  2. Material (Broad) Theory: Adopted by Pompe and Jonkers, this view states that changes in legislation include changes in the legal feelings or legal beliefs of society. If norms outside the Criminal Code change and affect the illegality of an act, then this principle must be applied.
  3. Limited Material Theory: A middle ground often referred to in modern practice (in line with H.R. Utrecht's view) is that changes outside the Criminal Code can be considered as changes in legislation if the changes are based on changes in legal assessment (gewijzigd rechtsinzicht), not just changes in factual situations.

Parameters for Determining "The Most Advantageous"

In judicial practice, judges are required to carefully make comparisons apple-to-apple between old and new rules in concreto. The parameters used include:

  • Decriminalization: This is the most advantageous form. If the new rule removes the offense, then the charges are null and void.
  • Principal Criminal Sanction: Judges compare the severity of the sanctions. Changes from imprisonment to fines, or a reduction in the maximum prison sentence, clearly benefit the defendant.
  • Changes in the Type of Offense: Changes from an ordinary offense to a complaint offense (klacht delict) are very beneficial to the defendant, because prosecution depends on whether or not there is a complaint from the victim.
  • Sentencing System: The New Criminal Code introduces social work and supervision as alternatives to short-term imprisonment. This option is certainly more advantageous than mere physical confinement.

Constitutional Dimension: The Role of the Constitutional Court

As the guardian of the constitution (The Guardian of Constitution), the Constitutional Court (MK) plays a central role. Article 28I paragraph (1) of the 1945 Constitution guarantees the right not to be prosecuted on the basis of retroactive law as a non-derogable human right (non-derogable rights).

However, the Constitutional Court, through its various decisions, has affirmed that the prohibition of retroactivity does not apply if the new rule is advantageous to the defendant (retroaktif in mitius). The principle is Lex Favor Reo seen as a derivative of the right to justice guaranteed by the constitution. When the Constitutional Court annuls a criminal norm in Judicial ReviewIn essence, the verdict constitutes the most beneficial "change of law," thus necessitating its immediate application to those undergoing the judicial process.

Conclusion

Principle Lex Favor Reo is evidence that Indonesian criminal law does not turn a blind eye to changes in the value of justice. During the transition period for the full implementation of the National Criminal Code in 2026, a deep understanding of this principle becomes crucial for law enforcement officials, academics, and legal practitioners. It ensures that no citizen falls victim to the rigidity of legal transition, upholding the adage that law must serve justice, not the other way around.