Before the United States Constitution was ratified there was much debate about what war powers the executive and legislative branches should hold. After much deliberation it was decided that the power to declare war would fall under the control of Congress. But as time passed, control over initiating military action began to shift from Congress to the President. This thesis examines the shift of power from the legislature to the President. The thesis explains the difference between a declaration of war, an authorization of force, as well as using the military as a police force. It examines the precedents set by Presidents Abraham Lincoln, Franklin Roosevelt, and Harry Truman, as well as the more recent methods used by Presidents Bill Clinton, George W. Bush, and Barack Obama. It also analyzes some of the major court cases that have dealt with the War Powers Clause and several War Powers Resolution. The information collected in this thesis comes from biographies, journal articles, and newspaper articles regarding the subject. This thesis shows that the executive has taken more power in initiating and continuing armed conflict and that the declaration of war, as defined in the Constitution, is obsolete.