Courts and Federalism examines recent developments in the judicial review of federalism in the United States, Australia, and Canada. Gerald Baier argues that the judicial review of Canadian federalism is under-investigated by political scientists. New institutionalist literature in political science suggests that courts matter as sites of governmental conflict and that they rely on processes of reasoning and decision making that can be distinguished from the political. Baier proposes that the idea of judicial doctrine is necessary to a better understanding of judicial reasoning, especially about federalism. To bolster this assertion, he presents detailed surveys of recent judicial doctrine in the US, Australia, and Canada. The evidence demonstrates two things: first, that specific, traceable doctrines are commonly used to settle division-of-power disputes, and second, that the use of doctrine in judicial reasoning makes a positive contribution to the operation of a federal system.