Since the turn of the twenty-first century, Canadian unions have scored a number of important Supreme Court victories, securing constitutional rights to picket, bargain collectively, and strike. But how did the labour movement, historically hostile to judicial intervention in labour relations, come to embrace legal activism as a first line of defense as opposed to a last resort? Unions in Court documents the evolution of the Canadian labour movement's engagement with the Charter, demonstrating how and why labour has adopted a controversial, Charter-based legal strategy to challenge and change legislation that restricts union rights. This book's in-depth examination of constitutional labour rights will have critical implications for labour movements as well as activists in other fields.