The department is headed by the Secretary of State who is the president's principal official advisor on foreign policy; although this role has sometimes been assumed by the National Security Advisor. The secretary is assisted by a deputy secretary and four undersecretaries; with access to ambassadors who have the ability to negotiate around the world. Although the department has many other functions such as educational and cultural affairs and economic and trade affairs, the main focus of the department is to maintain relations with other countries around the world. The Department's agenda may at times conflict with the Department of Defense's agenda regarding foreign threat, with the State Department advocating the power of diplomacy and the Department of Defense encouraging the use of action military. A good example occurred during the Cuban Missile Crisis where the Department of Defense promoted air strikes against Cuba while the State Department relied on diplomatic channels through the United Nations. Such opinions from both departments have made decisions more complicated for the