Final answer:
Congress is most likely to defer to the President in the area of foreign policy, a concept supported by the "Two Presidencies Thesis." The President tends to have greater autonomy here due to the need for a cohesive national voice on international matters and congressional powers such as budgetary controls that are more passive in this domain.
Step-by-step explanation:
In terms of policy areas where Congress is most likely to defer to the President, history and the institutional design of the United States government suggest that the area of foreign policy is where this deference is most commonly observed. This phenomenon is known as the "Two Presidencies Thesis," emphasizing that the president has greater autonomy in foreign than domestic policy. Aspects that contribute to this include the urgency that often accompanies international affairs, the need for a singular national voice, and congressional powers that are less front-and-center in foreign policy compared to domestic issues. These include approving treaties, oversight, and budgetary control. Additionally, there tends to be a rallying effect around the chief executive during foreign policy crises, and historically speaking, foreign policy is seen as less influenced by partisan disagreements and more by a shared national interest.
It's noteworthy that while the president is seen as the country's leader on foreign matters, Congress still wields significant power through its budgetary authority and can influence the direction of foreign policy through its control of funding. Additionally, during times when the economy is strong, Congress and the President may engage in expansionary fiscal policies, as seen in historical precedent, but this does not typically lead to congressional deference to the President more than in the realm of foreign policy.