Research on social movements and public policy has expanded tremendously in recent years, yet little of this work considers the role of movement opponents in the political process or how the movement-countermovement dynamic is influential in contests over policy. This historical study begins to fill this void by analyzing the contestation between employers and labor movement actors in relation to two critical right-to-work campaigns in the industrial Midwest in the 1950s. I find that actors who balance formal, professionalized organization with a more localized presence on the ground are in a better position to pursue multiple mechanisms of influence and to shape policy, while internal divisions severely limit their prospects. Event structure analyses of right-to-work campaigns advance this discussion, revealing how social movement organizational characteristics matter to the extent that they enable opposing movements to counter each other's actions in unfolding political processes. I conclude by discussing the implications of the findings for perspectives on social movements and politics, and for research dealing specifically with the U.S. labor movement. (Contains 3 tables, 3 figures and 8 notes.)