"De mortuis nil nisi bonum." Of the dead, nothing but good. So said Dean Acheson of Sen. Joe McCarthy on his death in 1957. "Tailgunner Joe" had bedeviled the secretary of state for his lassitude toward communist penetration of State in President Truman's time. But the passing of Mark Felt, associate director of the FBI in the later Nixon years, lately exposed as "Deep Throat," the source for the Woodward-Bernstein stories, calls forth some rebuttal to the tributes lavished upon Felt as the honest lawman who saved our republic. When the Watergate break-in was traced to the Committee to Reelect...