Retroactivity and Retrospectivity of Legal Effects

The Constitution of the Republic of Slovenia prohibits retroactive legal effect of statutes and provides four cumulative conditions that must be met for retroactive legal effect to be exceptionally permissible. The theory and constitutional case law in this area are extensive and must be considered by the legislator when enacting a law with retroactive effect. However, the Constitution does not specifically regulate the retrospectivity of legal effects, which is why constitutional case law has developed it based on the principle of the protection of legitimate expectations, which is rooted in the rule of law. Retrospective effect, as opposed to retroactive effect, is permissible, but the legislator must avoid acting arbitrarily and may worsen the legal position of the addressees only if there is a substantive reason based on an overriding, legitimate and constitutionally permissible public interest, having regard to the principles of proportionality and equality before the law. When amending an existing regulation which worsens the legal position of the addressees, the legislator must weigh legislative interference against the principle of the protection of legitimate expectations.

Keywords: retroactivity, retrospectivity, principle of the protection of legitimate expectations, public interest, acquired rights.