Federalism is still a relevant and vital aspect of Canadian Constitutional Law. Although a lower profile aspect than the Charter of Rights and Aboriginal rights (and in common parlance less "sexy"), the division of powers continues to an important part of the work of the Supreme Court of Canada and part of what defines us as a nation. The author argues that the Supreme Court has pursued an increasingly contextualized approach to division of powers issues - one that abandons the arid legalism of earlier days, in favour of a broad social analysis of issues based on extensive use of extrinsic evidence and academic commentary. He asserts that the role of the Court on these important matters of federalism is not just that of the traditional umpire, but rather the more active role of player - albeit a different kind of player than the front-line politicians. To illustrate this point Professor MacKay analyzes the federalism cases of the Laskin, Dickson, and Lamer Courts, with a particular emphasis on the latter Court, which on matters of federalism was dominated by Justice La Forest. The focus of this federalism case study is on the expansion of the criminal law power with particular reference to the Hydro Québec case. The author concludes that the Court has generally served Canadians well on matters of federalism and its justices are appropriately players in Canada's constitutional drama.