The one-voice doctrine, a mainstay of U.S. foreign relations jurisprudence, maintains that in its external relations the United States must be able to speak with one voice. The doctrine has been used to answer critical questions about the foreign affairs powers of the President, Congress, the courts, and U.S. states. Notwithstanding its prominence, the one-voice doctrine has received relatively little sustained attention. This Article offers the first comprehensive assessment of the doctrine. The assessment proves fatal.
Despite broad use and value in certain contexts, the one-voice doctrine is fundamentally flawed. The doctrine not only is used to address divergent questions concerning the allocation of foreign affairs authority, but masks different theories of constitutional interpretation; conflicts with constitutional text, structure, and history; diverges from actual practice; and fails to account for functional reasons why the United States might benefit from more than one voice in foreign affairs. In light of these failings, this Article concludes that it is time to discard the one-voice doctrine. At best, the doctrine might linger in the form of functional arguments that the need for one voice is compelling in particular cases. Unfortunately, even in this stripped down form, the one-voice notion faces steep hurdles as the courts, in contrast to the political branches, lack competence to identify the contexts in which the United States should speak with one voice in foreign affairs.