State of emergencyA state of emergency is a situation in which a government is empowered to put through policies that it would normally not be permitted to do, for the safety and protection of its citizens. A government can declare such a state during a natural disaster, civil unrest, armed conflict, medical pandemic or epidemic or other biosecurity risk. Under international law, rights and freedoms may be suspended during a state of emergency, depending on the severity of the emergency and a government's policies.
Reserve powerIn a parliamentary or semi-presidential system of government, a reserve power, also known as discretionary power, is a power that may be exercised by the head of state without the approval of another branch or part of the government. Unlike in a presidential system of government, the head of state is generally constrained by the cabinet or the legislature in a parliamentary system, and most reserve powers are usable only in certain exceptional circumstances.
ConstitutionA constitution is the aggregate of fundamental principles or established precedents that constitute the legal basis of a polity, organisation or other type of entity, and commonly determines how that entity is to be governed. When these principles are written down into a single document or set of legal documents, those documents may be said to embody a written constitution; if they are encompassed in a single comprehensive document, it is said to embody a codified constitution.
Head of stateA head of state (or chief of state) is the public persona who officially embodies a state in its unity and legitimacy. Depending on the country's form of government and separation of powers, the head of state may be a ceremonial figurehead or concurrently the head of government and more (such as the president of the United States, who is also commander-in-chief of the United States Armed Forces). In a parliamentary system, such as the United Kingdom or India, the head of state usually has mostly ceremonial powers, with a separate head of government.