Foreign policy is formulated and implemented within the executive branch. The principal policy institutions are the departments of State and Defense, the National Security Council (NSC), and the CIA.
Department of State
The Department of State is most directly responsible for the conduct of foreign policy. The secretary of state is, in theory at least, the nation's chief foreign policy official. That role can be assumed by other officials in the administration. President Nixon relied much more heavily on Henry Kissinger when he served as Nixon's national security advisor than on Secretary of State William Rogers. The day-to-day diplomacy of the United States is carried out by the Foreign Service, which staffs American embassies and consulates around the world. Although many ambassadors are appointed for their political contributions rather than their knowledge of foreign affairs, the career Foreign Service officers are an invaluable source of information for policymakers.
Department of Defense
It is difficult, if not impossible, to separate the military from foreign policy. The Defense Department was created in 1949 through a consolidation of the War Department and the Department of the Navy (which included the Marine Corps), both of which were cabinet-level departments, and the U.S. Air Force. The secretary of defense can have tremendous influence on foreign policy, as did Robert McNamara, who served in the post under President John Kennedy and President Lyndon Johnson during the Vietnam War. The Joint Chiefs of Staff, who are the heads of the four branches of the armed services and a chairperson, provide advice to the president on military planning and strategy.
National Security Council
The National Security Council (NSC) is made up of the president and vice president, the secretaries of defense and state, the director of the CIA, the chair of the Joint Chiefs of Staff (the leadership council for the armed services), and about a dozen other government officials; it is headed by the national security advisor. The council is responsible for advising the president on foreign policy. The role of the NSC varies from administration to administration. Nixon, who was extremely knowledgeable about foreign affairs, relied on the NSC a great deal. Indeed, his national security advisor, Henry Kissinger, was intimately involved in opening relations with the People's Republic of China, and he represented the United States in the peace negotiations with North Vietnam. Condoleezza Rice also played an important role in this position during George W. Bush's first term; she was appointed secretary of state in 2005.
Central Intelligence Agency
Created at the end of World War II, the Central Intelligence Agency (CIA) collects, analyzes, evaluates, and disseminates information (intelligence) relating to the national security of the United States. Although the CIA uses a variety of means to gather information, most of it comes from simply reading both official and mass-market publications from around the world. The most controversial of the agency's activities are its covert operations, which have involved assassination, assisting in the overthrow of a government, and tampering with elections.
The CIA is not the country's only intelligence gathering arm. In addition, there is the National Security Agency (NSA), the Defense Intelligence Agency, which is part of the Department of Defense, the intelligence branches within each of the armed services, and intelligence units within other executive departments such as State, Treasury, Energy, and Homeland Security. The CIA and the rest of the intelligence agencies came in for significant criticism for the failure to fully understand the terrorist threat to the United States in the wake of September 11. The 9/11 Commission emphasized the need to restructure intelligence activities. This was accomplished to a degree with the appoint of a National Intelligence Director to head the intelligence community; the director is the main advisor to both the president and the NSC on intelligence as it impacts national security.