Commander-in-Chief
Commander-in-Chief (in NATO-lingo often C-in-C or CINC pronounced "sink") is the commander of all the military forces within a particular region or of all the military forces in a state.
Political title
While well-known Commanders-in-Chief often have been senior generals, many countries have the rule that the Head of State is Commander-in-Chief in times of peace. Historically, the term "commander-in-chief" was first used by Charles I of England in 1639. Colonial governors in the future United States used the title. The Constitution of the United States gives the title to the President of the United States, who "shall be Commander-in-Chief of the Army and Navy of the United States, and of the Militia of the several States, when called into the actual Service of the United States" (See the 1941 Declarations of War[1] (http://www.yale.edu/lawweb/avalon/wwii/dec/decmenu.htm) against Japan and Germany for how this call is made).
In democratic monarchies, the King or Queen is the symbolic Commander-in-Chief, though the active authority is exercised by the Prime Minister and the subordinate defense ministers. In a few Commonwealth Realms, Commander-in-Chief is the Governor General (though they perform this role in the Queen's name), while in colonies the Commander-in-Chief is the leader of the colonial power. In France, the President of the Republic has a title of Chef des Armées ("Commander of the Armies"), which is a legacy of the monarchy.
Before 1948 the Commander-in-Chief in India reported to the civilian Governor-General of India since independence the duties of the two posts were merged into a single office, the President of India, who in turn reports to the government of the Republic of India. This model has been emulated by most other Commonwealth republics.
Military title
During times of war, national governments often establish reigionally-based CINCs to deal with a paticular theater of war. Though subsidary to the national CINC, such local-level CINCs usually have full decision-making authority in order to improve efficency during war.
In the United States, the Goldwater-Nichols Defense Reorganization act of 1986 added a new level of CINC. Under Goldwater-Nichols regional CINCs were created to bring a local supreme commander to a conflict. The most well known of which is CINC CENTCOM, who was Norman Schwarzkopf during Operation Desert Storm.
On October 24, 2002, the U.S. Secretary of Defense announced that the title of Commander-in-Chief would be reserved for the President, and that armed forces CINCs would shorten their title to "commander." Since then, the title has taken a proeminent importance in the political debate in the United States in the context of the "War against Terrorism" [2] (http://www.washingtonpost.com/wp-dyn/articles/A16750-2004Sep12.html).