Daniel Williams in the Boston Review:
At the end of the Korean war in 1953, captured American soldiers were allowed to return home. To widespread amazement, some declined the offer and followed their captors to China. A popular explanation quickly emerged. The Chinese army had undertaken an unusual project with its prisoners of war: through intense and sustained attempts at persuasion—using tactics such as sleep deprivation, solitary confinement, and exposure to propaganda—it had sought to convince them of the superiority of communism over capitalism. Amid the general paranoia of 1950s McCarthyism, the fact that such techniques had apparently achieved some success produced considerable alarm. The soldiers had been “brainwashed”—and everyone was vulnerable.
The ensuing panic over mind control stoked a frenzied search for solutions. How could the American public be protected against this new menace? William J. McGuire, a young and ambitious social psychologist, was among those who took up the challenge. McGuire’s big idea was to liken brainwashing to a viral infection. In such cases, post-infection treatment can help, but it is far better to inoculate individuals before they are exposed. Bolstered by a series of experiments that seemed to support his conjecture, McGuire ran with this analogy.
More here.