This article examines the reasons why the Knights of Labour, a labor movement that enjoyed enormous popularity and success during the penultimate decade of the 19th century, were unable to construct a resonant cultural frame in support of their platform of arbitration. The theoretical framework employed in this article is constructed by importing two concepts from political process models of social movement action into culturalist accounts, historical environment (or context), and opportunity. This framework allows me to look at how historical environments offer transient openings for the effective construction of counterhegemonic or subversive collective action frames. I argue that opportunity for framing has to do with the intersection between the signification requisites of framing practices, and the systemic features of cultural environments. I find that the nature of this opportunity in the years between 1885 and 1887 helps explain why movement practice within the Knights of Labour diverged so significantly from the practices advocated by its leadership.