Barack Obama stumbled at one point in his introduction of his vice presidential pick, telling the crowd in Springfield that he had come to “introduce you to the next President…the next Vice President of the United States of America: Joe Biden.”

But, in the last setting that will ever see Obama introducing Biden, it was the Vice Presidential candidate who drew the most raucous cheers from the crowd.

When Biden went after John McCain, with a vigor and, yes, a venom that has been missing from Obama’s stump speaking, it was a tonic for the troops who have been waiting for a campaign that is more prepared to throw punches than take them.

Biden was ready to rumble.

With echoes of Bruce Springsteen’s “The Rising” in the air, the senator from Delaware displayed a little of the old-school populism that Obama has so much trouble mustering – especially since securing the delegate support needed to claim the Democratic nomination.

Picking up on the Republican candidate’s admission that he does not know how many homes he owns–current estimate: seven–Biden noted that Americans are talking about tough economic times at their kitchen tables. But, he added, it’s different for McCain. “He’ll have to figure out which of the seven kitchen tables to sit at,” Biden quipped.

The crowd roared–not with laughter, but with relief.

The fight was being joined.

Biden pulled no punches, declaring himself to be “disappointed in my friend John McCain,” the man who once opposed George Bush for the Republican nomination but who had since become an ardent Bush backer.

“You can’t change America when you’ve supported George Bush 95 percent of the time,” Biden ripped.

“You can’t change America when you know that the your first four years as president will look exactly like George Bush’s last eight years,” he continued.

Yes, the senator from Delaware said, McCain may be “a friend of mine.”Yes, he said, McCain has a distinguished record of military service and still “wants to do right by America.”

But, said Biden, “These times require more than a good soldier, they require a wise leader.”

Obama, seated behind Biden, simply smiled.

Despite Obama’s initial stumble, Joe Biden is not the next President of the United States.

But Biden might add just enough of a political edge to make Barack Obama the next President of the United States.