Abstract

Scholars have debated the meaning of the foreign-relations clauses in the U.S. Constitution. This essay attempts to outline the foreign-relations clauses that an ideal constitution should have. A liberal constitution must enable the government to implement a morally defensible foreign policy. The first priority is the defense of liberty. The constitution must allow the government to effectively defend persons, territory, and liberal institutions themselves. The liberal government should also contribute to the advancement of global freedom, subject to a number of conditions, especially cost. The essay recommends improved methods to incorporate treaties and customary international law into the constitutional structure. Treaties should be approved by the whole legislature and should generally be self-executing. Customary law should be genuine, not fake, and consistent with liberal principles. Finally, based on economic theory and evidence, the essay recommends that liberal constitutions prohibit the government from erecting trade barriers. It concludes by tentatively proposing concrete constitutional language to implement these recommendations.