Article II, Section 2, of the U.S. Constitution states that the president is the commander in chief of the U.S. Army, Navy, and, when it is called into federal service, state militias (now called the National Guard). Historically, presidents have used this authority to commit U.S. troops without a formal declaration of war. However, Article I, Section 8, of the Constitution reserves to Congress the power to raise and support the armed forces as well as the sole authority to declare war. These competing powers have been the source of controversy between the legislative and executive branches over war making, so much so that in 1973 Congress enacted the War Powers Resolution, which limits the president’s authority to use the armed forces without specific congressional authorization, in an attempt to increase and clarify Congress’s control over the use of the military. In addition, the armed forces operate under the doctrine of civilian control, which means that only the president or statutory deputies—such as the secretary and deputy secretary of defense—can order the use of force. The chain of command is structured to ensure that the military cannot undertake actions without civilian approval or knowledge.