Theexecutive branch is the part of government which executes or enforces the law.

The scope of executive power varies greatly depending on the political context in which it emerges, and it can change over time in a given country. In democratic countries, the executive often exercises broad influence over national politics, though limitations are often applied to the executive.^[1]

Inpolitical systems based on theseparation of powers, governmentauthority is distributed between several branches to prevent power from being concentrated in the hands of a single person or group. To achieve this, each branch is subject to checks by the other two; in general, the role of thelegislature is to pass laws, which are then enforced by the executive, and interpreted by thejudiciary. The executive can also be the source of certain types of law or law-derived rules, such as adecree orexecutive order.

In those that usefusion of powers, typicallyparliamentary systems, such as theUnited Kingdom, the executive forms the government, and its members generally belong to the political party that controls the legislature. Since the executive requires the support and approval of the legislature, the two bodies are "fused" together, rather than being independent. The principle ofparliamentary sovereignty means powers possessed by the executive are solely dependent on those granted by the legislature, which can also subject its actions to judicial review. However, the executive often has wide-ranging powers stemming from the control of the governmentbureaucracy, especially in the areas of overalleconomic orforeign policy.

Inparliamentary systems, the executive isresponsible to the elected legislature, which must maintain the confidence of the legislature or one part of it, if bicameral. In certain circumstances (varying by state), the legislature can express its lack of confidence in the executive, which causes either a change in the governing party or group of parties or a general election. Parliamentary systems have a head of government (who leads the executive, often calledministers) normally distinct from the head of state (who continues through governmental and electoral changes). In theWestminster type of parliamentary system, the principle of separation of powers is not as entrenched as in some others. Members of the executive (ministers), are also members of the legislature, and hence play an important part in both the writing and enforcing of law. Inpresidential systems, the directly elected head of government appoints the ministers. The ministers can be directly elected by the voters.^[2]

In this context, the executive consists of a leader or leader of an office or multiple offices. Specifically, the top leadership roles of the executive branch may include:

• head of state – often themonarch, thepresident or the supreme leader, the chief representative and living symbol of national unity.
  • head of government – often theprime minister, overseeing theadministration of all affairs of state.
    • defence minister – overseeing thearmed forces, determining military policy, and managing external safety.
    • interior minister – overseeing thepolice forces, enforcing the law, and managing internal control.
    • foreign minister – overseeing thediplomatic service, determiningforeign policy and managingforeign relations.
    • finance minister – overseeing the treasury, determiningfiscal policy and managingnational budget.
    • justice minister – overseeing criminal prosecutions, corrections, enforcement of court orders.

In apresidential system, the leader of the executive is both the head of state and government.^[3] In some cases, such asSouth Korea, there is a Prime Minister who assists the President, but who is not the head of government but is the second in the chain.

In aparliamentary system, acabinetminister responsible to thelegislature is the head of government, while the head of state is usually a largely ceremonial monarch or president.^[4]

• Constitution
• Diarchy
• Legal reform
• Rule according to higher law