Just four months after Richard Nixon's resignation, New York Times reporter Seymour Hersh unearthed a new case of government abuse of power: the CIA had launched a domestic spying program of Orwellian proportions against American dissidents during the Vietnam War. The country's best investigative journalists and members of Congress quickly mobilized to probe a scandal that seemed certain to rock the foundations of this secret government. Subsequent investigations disclosed that the CIA had plotted to kill foreign leaders and that the FBI had harassed civil rights and student groups....