WASHINGTON -- She threw the kitchen sink at him. Accused Barack Obama of plagiarism. Mocked his eloquence. Questioned his truthfulness about NAFTA.

Wasn't enough. Hillary Clinton still faced extinction in Ohio and Texas. So what do you do when you have thrown the kitchen sink? Drop the atomic bomb.

Hence that brilliant "phone call at the White House at 3 a.m." commercial. In the great tradition of Lyndon Johnson's "Daisy" ad, it was not subtle -- though in 2008 you don't actually show the nuclear explosion. It's enough just to suggest an apocalyptic crisis.

Ostensibly the ad was about experience. It wasn't. It was about familiarity. After all, as Obama pointed out, what exactly is the experience that prepares Hillary to answer the red phone at 3 a.m.?

She was raising a deeper question: Do you really know who this guy is? After a whirlwind courtship with this elegant man who rode into town just yesterday, are you really prepared to entrust him with your children, the major props in the ad?

After months of fruitlessly shadowboxing an ethereal opponent made up of equal parts hope, rhetoric and enthusiasm, Clinton had finally made contact with the enemy. The doubts she raised created just enough buyer's remorse to convince Democrats on Tuesday to not yet close the sale on the mysterious stranger.

The only way either Clinton or John McCain can defeat an opponent as dazzlingly new and fresh as Obama is to ask: Do you really know this guy?

Or the corollary: Is he really who he says he is? I'm not talking about scurrilous innuendo about his origins, religion or upbringing. I'm talking about the full-fledged man who presents himself to the country in remarkably grandiose terms as a healer, a conciliator, a uniter.

This, after all, is his major appeal. What makes him different from the other candidates, from the "old politics" he disdains, is the promise to rise above party, to take us beyond ideology and other archaic divisions, and bring us together as "one nation."

It's worked. When Americans are asked who can unite us, 67 percent say Obama versus 34 percent for Clinton, with McCain at 51.

How did Obama pull that off? By riding one of the great non sequiturs of modern American politics.

It goes like this. Because Obama transcends race, it is therefore assumed that he will transcend everything else -- divisions of region, class, party, generation and ideology. Continued...