Judicial review is a process under which a government's executive, legislative, or administrative actions are subject to review by the judiciary. In a judicial review, a court may invalidate laws, acts, or governmental actions that are incompatible with a higher authority. For example, an executive decision may be invalidated for being unlawful, or a statute may be invalidated for violating the terms of a constitution. Judicial review is one of the checks and balances in the separation of powers—the power of the judiciary to supervise the legislative and executive branches when the latter exceed their authority. The doctrine varies between jurisdictions, so the procedure and scope of judicial review may differ between and within countries.