For decades following the failures of the Meech Lake and Charlottetown Accords constitutional debate in Canada appeared largely dormant. This situation has changed markedly in recent years. Since 2021 Alberta has held a provincial referendum proposing the abolition of equalization, Quebec and Saskatchewan have each unilaterally amended the 1867 Constitution Act, and a bilateral constitutional amendment concerning Saskatchewan has been proclaimed with the support of Parliament. Amid the stagnation that has characterized constitutional amendment processes from the early 1990s onward, these developments are highly significant. They signal a renewed dynamism in Canadian constitutional politics driven by provincial action and warranting careful and systematic analysis. Bringing together contributions from leading experts, From Multilateral Failures to Unilateral Successes? maps the impacts of recent and ongoing constitutional developments. Chapters examine instances of unilateral provincial action, offer analytical perspectives on the broader implications of these developments for federal authority, and explore the conditions under which provincial unilateralism may succeed. As the book shows, these initiatives operate within a political and constitutional framework where bilateral and multilateral options remain available but under-exploited. At a moment when the Canadian constitution is once again being tested and reshaped, this volume makes a timely and essential contribution, demonstrating that constitutional change is not only possible but already underway.