From the 1890s to World War I, progressive reformers in the United States called upon their local, state, and federal governments to revitalize American democracy and address the most harmful social consequences of industrialization. The emergence of an increasingly powerful administrative state, which intervened on behalf of the public welfare in the economy and society, generated significant levels of conflict. Some of the opposition came from conservative business interests, who denounced state labor laws and other market regulations as meddlesome interferences with liberty of contract. But the historical record of the Progressive Era also reveals a broad undercurrent of resistance from ordinary Americans, who fought for personal liberty against the growth of police power in such areas as public health administration and the regulation of radical speech. Their struggles in the streets, statehouses, and courtrooms of the United States in the early 20th century shaped the legal culture of the period and revealed the contested meaning of individual liberty in a new social age.