This study examines attempts by authorities to undermine overt collective challenges, such as protests, riots, or armed attacks, by targeting activities that precede and/or support such behavior. After providing a theory of how repression and resistance develop, the study analyzes unique data drawn from the confidential records of the Guatemalan National Police to assess the use of repression during the years between 1975 and 1985. Empirical tests demonstrate that (1) government forces anticipate challenger development by identifying the mobilization activities nascent challengers rely on to initiate and sustain overt collective challenges and (2) the use of repression designed to undermine such efforts is specifically targeted against radical (i.e., highly transformative) claims making. Implications are drawn for how we understand and study political order and conflict.