How did the Fathers of Canadian Confederation understand United States federalism? What lessons did they presume to draw from it and how did they apply them to the Confederation project? In this article, James Madison's comprehensive test of federalism, as set out in the thirty-ninth paper of The Federalist, is used as a tool to examine the Canadians' views of American federalism, particularly in relation to the questions of state sovereignty and the role of an upper chamber. The article suggests that their preoccupation with the threat of state sovereignty led them to concentrate on division of powers issues and, as a result, to pay little attention to the federal possibilities of a second chamber. And it concludes that, because they were working with a parliamentary model of government, not a republican one, these possibilities were not—and are not now—as promising as some political scientists suggest.