Like millions of other Americans whose avid, expert scorekeeping she finds somewhat surprising, Mary McCarthy watched the Watergate hearings and took the measure of the witnesses. Her reviews of the proceedings -- as theater as well as politics -- recall how the sessions at first moved along in, as Ervin phrased it, the ""spirit of wonderful unanimity"" and a confessional atmosphere. Although she wisely suspects the sincerity of both the confessor Baker and penitent Magruder, she notes that the hearings really lost their momentum with Mitchell, obviously a ruined man but unwilling to play the role either of adversary or informant. Ehrlichman and Haldeman, whose good guy/bad guy performance she compares to the classic Mutt and Jeff technique used by teams of interrogators to intimidate, were more satisfactory as actors, but in McCarthy's opinion the Committee abdicated its mission in its failure to call Colson -- ""in my view the key figure."" Of course, with or without Colson's testimony, McCarthy has drawn her own conclusions by this time and she minces no words: ""Ask when the arch-conspirator first got word of his conspiracy or when our wicked creator first got news of this wicked world"" -- Nixon is the one. This answer no doubt reinforces what a majority or near majority of Americans are thinking, and it was reached by the same method most of them used -- a combination of hard evidence and character analysis, a process of elimination after which the cheese stands alone. . . and implicated. The reasoning, however, has its points of interest, among them the hypothesis that, incredible as it seems, Mitchell never did ask Nixon what he knew, simply because he was afraid to hear the answer. One follows McCarthy for just this sort of insight, which reinvigorates jaded appetites and revives the spirit of amateur detection and civic outrage that made conversation so rewarding when the hearings were first bringing the ease before the public. McCarthy appeals as one shrewd outsider to another.