During a televised campaign debate with John F. Kennedy on Oct. 13, 1960, Richard M. Nixon sanctimoniously criticized the salty language of Harry S. Truman. Now the transcripts of Nixon’s Watergate tapes publicly reveal what many White House insiders already knew—that Nixon uses plenty of X-rated expletives. Those who have heard him speak in private say that the swearwords he commonly uses are both blasphemous and obscene; they include four-letter expletives that are salacious and scatological.