The impact of socialist ideas on U.S. labor movements was significant in the late 19th and early 20th centuries, as they provided a framework for advocating workers' rights. The introduction of socialist theories promoted concepts like collective bargaining and worker cooperatives, influencing labor unions to demand better wages and working conditions. Events such as the Haymarket Affair and the formation of the Industrial Workers of the World exemplified the growing alignment of labor activism with socialist ideals. This helped to galvanize workers against exploitation, pushing for fundamental changes in labor laws and practices.