Andrew Delbanco is the Levi Professor in the Humanities and director of American Studies at Columbia University.

I'm a neophyte blogger, so maybe I'll doubt myself in the morning--but tonight Clinton defied my expectations. I had expected his speech to be at least a disappointment and perhaps a disgrace. He seemed outrageous Tuesday night, mouthing his devotion ("I love you, I love you") putatively to Hillary but actually to the mass TV audience, as if he wanted it deliberately unclear to whom he was professing his devotion--wife, or fans, or both. Tonight I figured he'd carry on in the same vein, talking apparently about his party's nominee but actually about himself. Hillary had done that to perfection last night with her mantra of "keep on going, keep on going"--her appeal to the faithful to keep the faith til 2012--while staying studiously reticent about Senator Obama, of whom she surely should have said more, more warmly, and with more conviction.

But I've got to hand it to him: What Hillary failed to do, Bill did with great style. With how much conviction, who knows?

"We gotta get on with the show" were his first words after the multiple aw-shucks thank yous. And quite a show it was. There were moments when I wondered if, like his wife, he was sending the nominee a coded message. "I love Joe Biden," he said, before calling Hillary's speech "magnificent." And then, with suspense building over whether he would really come out swinging for Barack, he gave us a sort of policy wonk's parenthesis, listing the Republicans' failings: mortgage foreclosure, credit card debt, income disparity, unilateralism in foreign affairs. It was the old Bill, with his uncanny ability to be professorial and populist at once.

But then he really delivered. It was the first time in the course of the convention (leaving aside Michelle Obama's tender remarks, and Ted Kennedy's valiant but truncated appeal) that I heard someone speak convincingly of why Obama is the right man at the right time. Clinton's emphasis on Obama's "unique capacity" to lead our increasingly multicultural society was an overdue point, as if all the other speakers had been too squeamish to say it. He hit a good theme by imputing to Obama the same combination of reasonableness and toughness that he claims, with some justice, for himself. And he introduced into his speech a note of rhetorical elegance with stylish phrasings: From the Republicans all we got was "Katrina and cronyism." In Obama we will get a president who knows that "the power of our example is more impressive than the example of our power." That last one will be remembered, I suspect.

I also suspect that, reading the speech tomorrow, I'll detect some evasions. Because of Joe Biden, Clinton said, "America will have the national security leadership we need." Was there a dig there at the head of the ticket? "Yes he can," he said, nodding to the crowd as it went into its "yes we can" mantra--"but first we have to elect him," a rallying cry, yes, but also a warning not to harbor unrealistic hopes. This man might lose, and look who told you so. And then, toward the end of the speech, Bill managed to turn self-congratulation ("The Republicans said I was too young and too experienced to be commander-in-chief"!) into praise for his prospective successor.

It was a virtuoso performance. Yesterday, after Hillary's speech, I was convinced that the Clintons were preparing the groundwork for an Obama defeat that would not be laid at their feet so they would be the ones left standing. I am still appalled by how much the Republicans are borrowing from the Clintons' playbook: the stress on Obama's inexperience, the not-so-sly suggestions that he's a flash in the pan, an elitist, a little bit uppity, a little bit slick (that's a laugh from slick Willy). But tonight, Bill blew me away. He showed again that he's an utterly masterful politician--part scoundrel, part demagogue, but finally so sharp and charming that one wants to forgive him and suspend all suspicion. I only hope the Clintonites--all 18 million of them--heard and believed.

--Andrew Delbanco

Read Andrew Delbanco's literary analysis of Barack Obama's books.