After decades of decline, strikes have re-emerged across the United States since 2018. Much of the literature on union revitalization has bypassed the role of strikes, arguing that labor’s traditional weapon is ineffective in the twenty-first century. In this thesis, the author argues that strikes remain an important component of union revitalization. He answers three related questions regarding strikes as a source of union revitalization and the factors that lead to strike activity through a case study of a militant nurse union in California. In the major campaign analyzed, nurses struck nine times over a two-year period to preserve their collective bargaining agreement against nearly 100 proposed concessions. The role of leadership and identity emerged as important factors in strike incidence and sustaining militancy over time.