Commander-in-chief

A commander-in-chief is the person exercising supreme command authority of a nation's military forces or significant element of those forces. In the latter case, the force element may be defined as those forces within a particular region or those forces which are associated by function. As a practical term it refers to the military competencies that reside in a nation-state's executive, Head of State and/or Head of Government. Often, a given country's commander-in-chief need not be or have been a commissioned officer or even a veteran, and it is by this legal statute that civilian control of the military is realized in states where it is constitutionally required.

The role of commander-in-chief derives from the Latin, imperator. Imperatores (commanders-in-chief) of the Roman Republic and Roman Empire possessed imperium (command) powers. In its modern usage, the term was first used by King Charles of England in 1639. A nation's head of state usually holds the position of national commander-in-chief, even if effective executive power is held by a separate head of government. Colonial governors are also often appointed commander-in-chief of the military forces in their colonies. Examples are Commander-in-Chief Allied Forces North, or Commander-in-Chief East Atlantic.

A Commander-in-Chief is sometimes referred to as Supreme Commander, which is sometimes used as a specific term. The term is also used for military officers who hold such power and authority, not always through dictatorship, and as a subordinate (usually) to a head of state. The term is also used for officers that hold authority over individual branches or within a theatre of operations

Within NATO and the European Union, the term Chief of Defence (CHOD) is usually used as a generic term for the highest military commanders of the NATO and EU member states, irrespective of their actual title.