Foreign relations law serves as an internal constraint on the unilateral exercise of foreign relations powers through the distribution of authority within the national government. Given the predominance of the executive branch in foreign affairs, courts routinely resolve questions regarding the breadth of the executive's authority by reference to the Constitution, legal precedent, historical practice, and functional considerations. Though courts generally focus on these domestic factors, they have been historically quite sensitive to the international political implications of their decisions. But we don't have a clear understanding of how or when courts consider international politics in resolving foreign relations law questions. We lack a framework to begin thinking about the relationship between international politics and the allocation of decisionmaking authority.
This short Article frames foreign relations law as a function of international politics to explore the relationship between the strength of external international political constraints on a state and the levels of judicial deference to the executive in that state. Variation in the structure of international politics bipolar, multipolar or unipolar - likely produces variation in the strength of external constraints on a state. This approach yields a simple descriptive claim and a related predictive claim. The stronger the external constraints on a state, such as the constraints present in multi-polar or bipolar worlds, the greater the likelihood of judicial deference to the executive on institutional competency grounds. Conversely, the weaker the external constraints on a state, such as the constraints present in a unipolar world, the lesser the likelihood of judicial deference to the executive. If this claim is accurate, it leads to a predictive claim that the rate of judicial deference to the executive will likely decrease as long as the United States is die hegemon of a unipolar world. This approach also provides a clearer picture of the overall level of constraint on the executive, helps describe the impact of external constraints on judicial deference, and explores the effects of international politics on the US's engagement with international law. Consider the following example:
Imagine a state with a constitution diat is over two hundred years old. Imagine that the state's constitution rests on a theory of separation of powers and provides a tripartite allocation of foreign relations law authority. The initial allocation to the legislative, executive, and judicial branches is short and incomplete, leaving many questions regarding the proper constitutional allocation to subsequent political and judicial resolution. Imagine further that the institutional power and influence of one branch - the executive - has grown dramatically since die initial allocation, often resulting in judicial deference to the executive on foreign relations questions because of historical practice, institutional competence, and greater political accountability. If the legislative branch of this state generally follows the executive as well, and die executive has institutional advantages in generating political support for its policies, the executive could then act in many instances with significant independence from domestic constitutional constraints.
Now one might pause to ask if this particular allocation of foreign relations law authority is problematic. Some might favor stronger internal constraints on executive authority, others weaker. For many, the debate might stop here. But this provides only a partial picture of the breaddi of executive audiority. We must turn to examining the strength of external constraints for a complete picture.
Our hypothetical state might pursue its interests in a world with two or more competing states of similar economic and military strength - a multipolar world with other great powers. In pursuing their national interests, these other great powers serve as external constraints on the executive; they represent an external disciplining force to moderate the executive's foreign relations decisionmaking. …