The first part of this study traces an evolution in relationships between vigilantes and federal domestic security agents in the United States of America between 1910 and1964. In the 1910s and 1920s moral panics regarding white slavery and radical unionism animated countersubversive efforts preserve the moral fabric of the Republic. A nascent domestic security bureaucracy worked in tandem with private detective agencies and vigilante groups. This resulted in extensive violations of civil liberties during the First World War and the Red Scare and injury to democratic political processes. Under pressure to reform, J. Edgar Hoover professionalised the Bureau of Investigation (BI) in 1924, ending the practice of deputizing vigilantes and breaking off overt ties with private detective agencies.1 Henceforth the BI would use covert surveillance and intelligence collection, as well as controlled informant penetration in its domestic security operations. During the Second World War and the early Cold War, the evolution of the Federal Bureau of Investigation into a domestic security state forced existing incongruities in American countersubversive mechanisms to the surface, leading to further insulation of Bureau processes from racists and ‘extremist’ anticommunists. In 1964 the FBI launched COINTELPRO-WHITE HATE, a covert action programme that aimed to ‘expose, disrupt and neutralize’ the United Klans of America (UKA) and other ‘extremist’ organisations, which were attempting to thwart implementation of federal civil rights legislation through agitation and terrorist violence. This study examines the FBI’s selection of targets for COINTELPRO-WHITE HATE as well as the its efforts to disengage vigilantes and other ‘extremists’ from an emerging network of cooperative law enforcement agencies, patriotic organizations and system-supportive vigilante groups. In so doing, it provides an analysis of one critical permutation in the development of American domestic security strategies during the Cold War.