Judicial review is the doctrine in democratic theory under which legislative and executive actions are subject to review, and possible invalidation, by the judiciary. Specific courts with judicial review power must annul the acts of the state when it finds them incompatible with a higher authority, such as the terms of a written constitution. Judicial review is an example of the functioning of separation of powers in a modern governmental system (where the judiciary is one of three branches of government). This principle is interpreted differently in different jurisdictions, which also have differing views on the different hierarchy of governmental norms. As a result, the procedure and scope of judicial review differs from country to country and state to state.