Policymakers and legal scholars routinely make “comparative institutional competence” claims—claims that one branch of government is better at performing a specified function than another, and that the more competent branch should be in charge of that function. Such claims pervade American law and policy, but they are rarely evaluated with rigor.
We take advantage of an unusual legislative experiment to conduct what we believe to be the first systematic empirical analysis of the comparative institutional competence of the executive and judicial branches in a critical field of American law and policy: U.S. foreign relations. From 1952 to 1976, the U.S. State Department decided whether foreign nations would receive sovereign immunity from suits in U.S. courts. Based on the perception that the State Department’s sovereign immunity decisions were overly influenced by political considerations, Congress passed the Foreign Sovereign Immunities Act of 1976 (FSIA), which transferred immunity decisionmaking authority to the judiciary. This transfer was based on an explicit comparative institutional competence claim: that courts are better equipped than the State Department to make immunity decisions based on law rather than politics.
To rigorously evaluate this fundamental claim, we created and analyzed an extensive dataset of foreign sovereign immunity decisions made by the State Department and the U.S. district courts over the last fifty years. Our principal findings are threefold. First, we find little evidence that political factors systematically influenced the State Department’s immunity decisions. Second, there is strong evidence that political factors have systematically influenced the courts’ decisions. Third, the transfer of immunity decisionmaking authority to the courts did not significantly affect the likelihood of immunity.
All three findings challenge both the underlying comparative institutional competence claims that supported the FSIA’s pas-sage and more general conventional understandings about the proper allocation of authority between the executive and judicial branches. To be sure, there may be valid reasons for the judiciary to play a leading role in immunity decisionmaking, and possibly other areas of U.S. foreign relations as well. But our analysis casts doubt on the widely made comparative institutional competence claim that the judicial branch is necessarily better equipped than the executive branch to make foreign relations law decisions free from systematic political influence.