Many aspects of foreign policymaking rely on the powers shared between Congress and the president, including foreign policy appointments and the foreign affairs budget. Within the executive branch, an array of foreign policy leaders report directly to the president. Foreign policy can at times seem fragmented and diffuse because of the complexity of actors and topics. However, the president is clearly the leader, having both formal authority and the ability to delegate to Congress, as explained in the two presidencies thesis. With this leadership, presidents at times can make foreign policymaking quick and decisive, especially when it calls for executive agreements and the military use of force.
two presidencies thesis: the thesis by Wildavsky that there are two distinct presidencies, one for foreign and one for domestic policy, and that presidents are more successful in foreign than domestic policy