""Well, when the president does it, that means it is not illegal," Nixon would later explain, in a lame attempt to justify the wiretaps and break-ins he had authorized in an effort to plug leaks within his administration regarding the conduct of the Vietnam War. "If the president, for example, approves something because of . . . national security, or in this case because of a threat to internal peace and order of significant magnitude, then the president s decision . . . enables those who carry it out to [do so] without violating a law." The claim was not a new one. Every chief executive since Franklin D. Roosevelt had sanctioned acts of questionable legality in the interests of national security, and Abraham Lincoln had done so more flagrantly than any of them in order to preserve national unity. Nixon, however, made several mistakes that were distinctly his own. The first was to exaggerate the problem confronting him: the leaking of The Pentagon Papers to the New York Times was not a threat comparable to secession in 1861, or to the prospect of subversion during World War II and the early Cold War. Nixon's second mistake was to employ such clumsy agents that they got themselves caught. And his third mistake—the one that ended his presidency—was to lie about what he had done in a futile attempt to cover it up. The Watergate might have remained only an episode in the domestic history of the United States except for one thing: distinctions between might and right were also beginning to affect the behavior of the Cold War superpowers. The last years of the Nixon administration marked the first point at which the United States and the Soviet Union encountered constraints that did not just come from the nuclear stalemate, or from the failure of ideologies to deliver what they had promised, or from challenges mounted by the deceptively "weak" against the apparently "strong." They came as well now from a growing insistence that the rule of law—or at least basic standards of human decency—should govern the actions of states, as well as those of the individuals who resided within them."