Commander in Chief (
CINC) usually refers to the ultimate
commander of the
armed forces of a
nation, though it can refer to the commander of any sufficiently large
military force.
Commander in Chief powers are reserved for an important head of state. In the United States of America, the President is the CINC. Although the CINC is the supreme commander of all departments of the military, the CINC does not have complete control over the military's actions.
In the United States, the Gulf of Tonkin resolution was an example of the President using (and some would say "abusing") the powers of the Commander in Chief to their fullest extent. Only Congress has the ability to declare war. The Gulf of Tonkin resolution allowed President Lyndon Baines Johnson to commit the American military to the situation developing in Vietnam without officially declaring war on Vietnam.