Richard Cohen--senior producer for political coverage at CBS News--is being informally disciplined for "speaking out of school" by his superiors, the Washington Post reported Wednesday. The paper said that Cohen was barred from the CBS News set in Des Moines, Iowa, Monday after a confrontation with news executives Joan Richman and David Buksbaum just as the network prepared to report on the key Iowa caucus results that evening. The executives had been angered by Cohen's apologetic remarks about the George Bush-Dan Rather on-air confrontation Jan. 29 to a Des Moines Register reporter. "I'd be the first to say we made a tactical error in agreeing to go live," Cohen was quoted as saying, "because you can't control a live situation. . . . We took a very heavy hit. . . . I think Dan (Rather) made mistakes." The Post said Cohen, who was back on the job at CBS election headquarters in Manchester, N.H., by Tuesday refused to comment on the story.