Investigations during the Iran-contra affair revealed a "shadow government," operating without public knowledge or congressional approval, being run out of the White House. For months, Reagan refused to admit that arms were traded for hostages -- that he had, indeed, negotiated with terrorists. Meanwhile, congressional hearings were convened to investigate the illegal diversion of funds to the contras. The all-too-familiar question of "what did the president know, and when did he know it," summoned up the ghosts of Watergate