Labor unions strive to reduce competitiveness and promote solidarity among their membership, and those in the U.S. construction industry also serve as job brokers between workers and employers. In this capacity, the attempts of unions to address the temporary nature of construction work through regulating the distribution of job assignments may inadvertently promote fierce competition between laborers. As workers struggle to make sense of their own fortunes in a tightening labor market and the diminished political clout of unions overall, the organizational structuring of competition produces labor fragmentation and calls into question appeals to solidarity. This paper examines the relationship between job brokerage, labor competition, and the organization of work among unionized construction workers in the Western United States. As the focus of building trade unions shifts from protecting workers' interests against the exploitation of management to functioning essentially as staffing agencies, our study illuminates the ways in which these unions become a locus for the articulation of difference rather than solidarity. It also illustrates the challenges faced by organized labor in addressing its seemingly contradictory role in facilitating both individualist and collectivist identity formations.