What is the key requirement of prospectivity in laws?

The key requirement of prospectivity in laws is that laws must apply to future actions. This principle ensures that individuals are able to understand the consequences of their behavior going forward and can base their decisions on the existing legal framework. It fosters fairness and stability within the legal system, allowing people to adapt to new laws before they are held accountable for their actions.

This concept prevents retrospective legislation, which would impose penalties or obligations for actions taken in the past based on new laws. A legal system that operates on the basis of prospective laws promotes transparency and predictability, enabling individuals to engage with the law in a way that is informed and equitable. Thus, the emphasis on future applicability reflects the foundational belief in justice and the rule of law.