Canada's population, a tenth that of the United States, is perched close to the U.S. northern border, tightly but asymmetrically tied to U.S. information networks. However, trade, capital and population mobility remains an order of magnitude tighter among provinces than between provinces and states. This separating effect of the national border is not primarily due to barriers, but to networks of contacts, trust and institutions that make it efficient to concentrate economic activity within national borders. This separation combines with quite different histories to explain why Canadian economic, social, education and health care policies remain distinct from U.S. policies, often closer to those in Northern Europe.