The use of specific presidential foreign policy consultants and personal envoys expanded during World War II and the postwar years. Franklin Roosevelt's use of Harry Hopkins and a "brain trust" of advisers contributed to the development of a separate White House office distinct from the existing cabinet departments such as the Department of State, although in large measure its emergence merely reflected the growth of the government that came with the increasing complexity of its functions in the modern world. It was Roosevelt, regarded as a strong chief executive, who initiated the development of the Executive Office of the president. By the 1950s there was an entirely separate White House staff of considerable size. Although only a small portion of it dealt with foreign policy, this portion was expanded under later presidents, eventually evolving into a sizable National Security Council (NSC).
The NSC, originally established as a small office in 1947, grew to importance during the administration of Richard M. Nixon. It has continued throughout all subsequent administrations as part of the White House staff, becoming virtually an alternate State Department functioning wholly under the president's control. While officially functioning as a coordinating body to assemble the recommendations of different agencies involved in foreign relations, it has provided the chief executive with a separate foreign affairs staff and enabled him to act independently in foreign affairs. Its power derives from proximity to the president and the ability to set agendas by providing the chief executive with daily morning security briefings that cover important international events. The NSC proved especially important during the height of the Cold War, when security and national defense matters assumed precedence over other aspects of foreign policy. The prominence of the NSC, however, has continued beyond the end of the Cold War.
The existence of White House foreign policy advisers, and the creation of the National Security Council within the Executive Office as a separate body, provides the president with a staff of specialists of his own, distinct from the State Department and the regular Foreign Service. This has strengthened the hand of the president in foreign affairs, enabling him to conduct his own policy through what virtually amounts to an alternate foreign office. That it is housed in the building formerly occupied by the State Department is symbolic both of the increased size of the two institutions (the State Department moved to larger quarters) and of the change in the relationship between the chief executive and the State Department.
The process of utilizing special representatives in the conduct of foreign affairs accelerated in the years after World War II, reflecting the increasing complexity of world affairs; the increasing interconnectedness of the world, known as globalization; and the larger involvement of the United States in international affairs. Security cooperation on global and regional scales expanded, and economic interchange between nations and across borders accelerated greatly. In the 1960s the demise of colonialism doubled the number of independent nations in the world and the number continued to increase afterward. In addition, more rapid communications and transportation links enabled rapid movement of goods, business, and citizens, which meant that governments needed to remain in much closer contact. It also meant that individual citizens and organizations interacted constantly with their counterparts in other nations, in addition to the interaction between their governments. Issues formerly regarded as exclusively domestic were now considered part of the international system, and many previously domestic concerns extended beyond borders and were regarded as global or regional problems to be addressed jointly and cooperatively by many nations. Many problems had to be addressed at the global level, since they affect peoples in many nations, regardless of borders.