What does Joe Biden bring to the Democratic ticket? The ability to speak knowledgeably about issues: "What's going on in Pakistan this very moment as I speak to you, what's going on in the [Indian] subcontinent overall, the Korean Peninsula, China, Hugo Chavez rewriting the constitution [of Venezuela] to make himself leader for life, and the democratization of Latin America--ladies and gentlemen, there's a great deal at stake."

Whew! Biden has been in the Senate for nearly 36 years. He knows Washington; he knows the world--two areas where Barack Obama's credentials are a little weak.

And he's from Delaware! Delaware? Just three electoral votes. Pretty reliably Democratic. Biden also has roots in Pennsylvania, a major swing state that Obama lost to Hillary Rodham Clinton in the primaries. Plus, Biden is Catholic. Catholics are swing voters. In the Democratic primaries, Catholics tended to vote for Clinton.

The big question now is what happens to Clinton's voters. Remember the Obama-Clinton "Dream Ticket"? That dream is over, and the Democratic Party has to pull together anyway. Will Obama's choice of Biden make that easier or harder?

More than one-third of Democrats say they would prefer to see their party nominate Clinton rather than Obama, according to a poll taken for CNN by Opinion Research after the choice of Biden was revealed. Among Clinton supporters, 27 percent say they intend to vote for John McCain. That's up from 16 percent in June.

Nearly 60 percent of Clinton supporters call Biden a good choice. Hillary Rosen, a prominent Clinton supporter and the Washington editor-at-large of The Huffington Post, said, "I think Hillary Clinton's supporters see someone who's a peer [of Clinton's]. They see somebody who has a similar amount of experience." Clinton biographer Carl Bernstein said, "My guess is, she thinks, next to herself, Biden is probably the best choice."

Thirty-eight percent of Democrats wanted Obama to choose Clinton as his running mate. But Clinton supporters are not complaining about Biden himself. They are complaining about the selection process and saying that Obama did not show Clinton proper respect. Former Clinton adviser Paul Begala said on CNN's Larry King Live, "I think there are a lot of Hillary voters who are going to say, 'Hey, wait a minute. You said you were going to put her on the short list. You didn't even vet her. You didn't call her. You didn't seek her advice."

Don't expect Clinton herself to express any resentment. Rosen said, "I think everyone wants to be asked, but I don't think she's dwelling on it or has dwelled on it. I think she's moving on."

The Clintons are likely to be good soldiers and to ask their supporters to be the same, because there is a larger principle at stake beyond personal ambition. As Bernstein explained, "One of the things the Clintons have always been about--and the Clinton presidency was about--is stopping the march of the Republican Right. Never forget that. That means an awful lot to Hillary and Bill Clinton."

Guess who is fomenting trouble between the Clinton and Obama camps? The McCain campaign sent out a mass e-mail to reporters shortly after the Biden announcement, saying, "It's pretty revealing that the Obama campaign chose to send their text message out at 3 a.m.--looks like one last inside-baseball attack on Hillary Clinton. How else would they explain it?"

The McCain campaign then released a television ad featuring, of all people, Hillary Clinton. "She won millions of votes," the announcer says. "But she isn't on the ticket. Why? For speaking the truth." Then comes several examples of Clinton criticizing Obama during the Democratic primaries. When was the ad released? Sunday morning, 3 a.m.

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