You're describing sunset clause or sunset provision! A law requires further legislative action for it to not disappear on a certain pre-set date. https://en.w

You're describing sunset clause or sunset provision! A law requires further legislative action for it to not disappear on a certain pre-set date. https://en.wikipedia.org/wiki/Sunset_provision https://en.wikipedia.org/wiki/Sunset_provision Another variation I think I read about is where the law is implemented with an explicit goal that must be achieved by a certain date, and if the goal is achieved, the law becomes a regular law; if the pre-defined metric is not met by the certain date, the law disappears.