This article attempts to expand our understanding of the effects of unions on the earnings of workers by examining several dimensions of union presence simultaneously. Specifically, the authors examine the direct effects of unions (union membership) and the indirect effects of intraindustry union threats (union density) and interindustry union threats (upstream and downstream unionization) on earnings inequality. The authors examine how these dimensions of union presence affect earnings of workers in different locations in the class structure using class distinctions developed by Wright (1985). They find that union presence has a complicated relationship to earnings of workers in different locations in the class structure. Although union membership positively affects the earnings of all workers, the positive effects of union density are confined to proletarians. Downstream unionization positively affects the earnings of both unionized and nonunionized managers and credentialed workers in a linear fashion. However, its positive effects on the earnings of proletarians are confined to the nonunionized and they are nonlinear. These results are interpreted in light of prior research on union threat effects and are compared to research on positional power by Wallace, Leicht, and Grant (1993).