Through analysis of two social issues that held the potential for anti-UNESCO campaigning by the American Radical Right in the 1950s – UNESCO’s much publicized Statements on Race and the use of UNESCO textbooks in public schools and libraries – I argue that micromobilization contexts can create conditions of path dependency whereby the initiation of one campaign hinders other campaigns from developing. Specific micromobilization factors – past campaigning on similar issues, tactical expectations, an available pool of skilled activists, frame resonance, a national conservative media, and amenable polities – created favorable initial conditions for anti-UNESCO censorship campaigning, while competition from activists in another social movement restricted campaign development in response to UNESCO’s Statement on Race. The micromobilization context from which the censorship campaign emerged created conditions of path dependency which limited further the viability of American Radical Rightists developing a campaign in reaction to UNESCO’s Statement on Race.