For most of the 19th century, the labor movements of England and America seemed to be developing along similar lines. Then, in the decades around the turn of the century, both movements were embroiled in a common battle over the political soul of trade unionism. In England, the champions of broad, class-based social and industrial reforms prevailed. In the United States, they lost, and the winners were the voluntarists, who held that labor should steer clear of politics as much as possible. This article suggests that the key reasons for the divergence lie not in the sociology of the working class or labor movement, so much as in the character of the state and polity and the lessons trade unionists drew from experiences in those arenas. The difference between judicial supremacy in the United States and parliamentary supremacy in England combined with other differences in the two nations’ forms of government to produce sharply contrasting lessons about the value of state-based reforms.