In early 1996, Canada's federal government enacted a new constitutional amending process to provide provincial and regional vetoes over future amendments. This study compares the new process with the “7 and 50” formula found in the Constitution Act, 1982. Using the Banzhaf Index as well as separate measures for the power to prevent and the power to initiate amendments, the article examines the relative influence of the provinces under the two amending formulae. As well, it examines the relative voting power of each province's citizens in any future constitutional referendum. The results show that profound changes are produced by the regional veto amending formula, and the article discusses some remedies for the most negative effects.