Dead last in the ratings, ABC hired two towering public intellectuals to debate each other during the Democratic and Republican national conventions. William F. Buckley Jr. was a leading light of the new conservative movement. A Democrat and cousin to Jackie Onassis, Gore Vidal was a leftist novelist and polemicist. Armed with deep-seated distrust and enmity, Vidal and Buckley believed each other's political ideologies were dangerous for America.

Detached and ironic; a master of the pointed put-down, of the cutting quip; enigmatic, impossible to truly know: This is the calcified, public image of Gore Vidal-one the man himself was fond of reinforcing. "I'm exactly as I appear," he once said of himself. "There is no warm, lovable person inside. Beneath my cold exterior, once you break the ice, you find cold water." Michael Mewshaw's Sympathy for the Devil, a memoir of his friendship with the...