What is the legacy of the Clinton presidency? Consolidator of the Reagan revolution. As Dwight Eisenhower made permanent FDR's New Deal and Tony Blair institutionalized Thatcherism, Clinton consolidated Reaganism. He did so most symbolically with his 1996 State of the Union declaration that "the era of big government is over." And more concretely, with a presidency that only tinkered with such structural Reaganite changes as tax cuts and deregulation, and whose major domestic achievement was the abolition of welfare, Reagan's ultimate social bete noire.

These are serious achievements, but of a second order. Obama did little more than echo that truism. But one can imagine how it made Clinton burn. He is, after all, a relatively young man who has decades to brood over his lost opportunity for greatness and yet is constitutionally barred from doing anything about it.

Except for the spousal loophole. Hence his desperation, especially after Hillary's Iowa debacle, to rescue his only chance for historical vindication -- a return to the White House as Hillary's co-president. A chance to serve three, perhaps even four terms, the longest in history, longer even than FDR. The opportunity to have dominated a full quarter-century of American history, relegating the George W. Bush years to a parenthesis within Clinton's legacy.

It was to save this one chance, his last chance, to be historically consequential, that Bill Clinton blithely jeopardized principle, friendships, racial harmony in his own party and his own popularity in South Carolina.

Why not? Clinton knows that popularity is cheap, easily lost, easily regained. (See Lewinsky scandal.) But historical legacies are forever.

He wants one, desperately. But to get it he must return to the White House. And for that he must elect his wife. At any cost.

Why was he out of control in South Carolina? He wasn't. He was clawing for a second chance.