In an era where federal-provincial tensions over Canada’s international commitments dominate headlines, a clear understanding of our nation’s foreign affairs powers has never been more crucial. Foreign Affairs in the Canadian Constitution analyzes how Canada’s foreign affairs power has been applied, and how it is defined within the law. Drawing on case studies from federal-provincial flashpoints over free trade in the 1980s to the showdown in the Supreme Court of Canada over federal climate change legislation, Scott Fairley bridges the silos of federal executive power cloaked in the royal prerogative and constitutionally divided federal and provincial legislative powers to define an integrated understanding of foreign affairs within Canada’s constitution. He also highlights this Canadian historical anomaly among federal states through comparative analyses of analogous countries, specifically Australia and the United States. He then makes the case that this anomaly has actually been resolved through constitutional evolution, governmental practice, and judicial interpretation which have firmly established foreign affairs as a constitutionally supported field of federal jurisdiction. This rigorously argued account enables a better understanding of Canada as a unified nation-state within the community of nations.