In the late 1950s, Washington was driven by its fear of communist subversion: it saw the hand of Kremlin behind developments at home and across the globe. The FBI was obsessed with the threat posed by American communist party--yet party membership had sunk so low, writes H.W. Brands, that it could have fit "inside a high-school gymnasium," and it was so heavily infiltrated that J. Edgar Hoover actually contemplated using his informers as a voting...