This paper examines whether protest associated with the "long protest wave" of the 1960s and 1970s positively influenced private-sector union support. Past research has found no such influence. We use measures designed to more closely represent the theoretical mechanisms proposed for spillover--specifically, union support rather than overall union density--and find a clear effect of protest on union support. Moreover, we find that this effect is greatest for unions with more progressive track records than for the labor movement as a whole. These results have implications for the social-movement literature on spillovers, labor studies, and organizational scholarship.
