Washington Post veteran Don Ober- dorfer, who concluded, as most historians do now, that the Commu- nists' spectacular 1968 Tet Offensive was a defeat for Hanoi in South Viet- nam, even as it demoralized political Washington. In The Unmaking of a President (19771, Herbert Schandler, a retired Army colonel and one of the authors of the Pentagon Papers, fol-lowed up with a scholarly, eye- opening dissection of Washington decision-making during the hectic February-March $968 period. An- other Postman,...