Organizational resources and group solidarity are central foci in literature on social movements generally and worker insurgency specifically. Research, however, seldom deals with both simultaneously and their potential interrelations. In this article, we examine the complex relationships between union organization and worker solidarity relative to strike action. We draw on a data set of 133 content-coded workplace ethnographies and use a combination of qualitative comparative analysis and more standard statistical techniques. Consistent with expectations, results suggest union presence and worker solidarity, in and of themselves, have little meaningful association with strikes. Rather, it is their co-presence that bolsters strike likelihood. Conversely, a lack of union presence in combination with a lack of collective mobilization history diminishes overall strike potential. We conclude by discussing the implications of our argument and findings for more general social movement perspectives as well as prior work dealing specifically with unions, solidarity, and collective resistance.