This article explores the relationship between federalism, treaties, and international rights under the Canadian Constitution. A comment on comparative analysis precedes the introduction to that project. Recognizing that the similarities and differences that distinguish federal states offer a distinctive source of insight, the discussion draws on American parallels when feasible. Even so, the article's main objective is to explain how Canada ratified and implemented international instruments in the face of the significant restrictions on the national government's treaty power. In general terms, after analyzing a constitutional jurisprudence that subordinated sovereignty in foreign relations to principles, of federalism, the article explores the process by which the constraints of the doctrine were overcome.