ABSTRACT
This chapter presents a comparison of the foreign policies of presidents Truman and Reagan to establish the impact the president has on the formulation of US foreign policy. It explains the sources and constraints of presidential autonomy. The chapter concerns the external environment each president confronts in the shape of the international system. President's worldview is crucial in determining the general orientation of US foreign policy during each administration. The chapter also focuses on the internal sources and constraints of the executive bureaucracy. The international system provides the external constraints each president must face in the formulation of foreign policy. The effect of the one group beginning to dominate as the president's worldview solidified towards the Cold War mindset helped overcome bureaucratic constraints as it brought a level of agreement amongst his top-level advisors, which was strengthened by Truman's formal system.
