The actual role of Vice President of the US varies from administration to administration. Joe Biden performed many sensitive tasks for "his boss," as he calls him - and Thursday night he took on himself just another one: to testify for Obama's character.

"Tonight what I really want to do is tell you about my friend Barack Obama... I want to take you inside the White House to see the president as I see him every day, because I don't see him in sound bites. I walk 30 paces down the hall into the Oval Office, and I see him, I watch him in action."

Biden spoke of the financial crisis, of the auto industry bailout, the loss of faith in America. "From the very moment President Obama sat behind the desk, resolute, in the Oval Office, he knew he had not only to restore the confidence of a nation, but he had to restore the confidence of the whole world. Day after day, night after night I sat beside him as he made one gutsy decision after the other to stop the slide and reverse it."

What drives Obama, Biden claimed, echoing the First Lady's remarks Tuesday night, is "his profound concern for the average American."

"One of the things I learned about Barack is the enormity of his heart. And I think he learned about me the depth of my loyalty to him... He never, never backs down. He always steps up, and he always asks in every one of those critical meetings the same fundamental question: How is this going to affect the average American?"

Biden spoke of his father, a car salesman, and the Republican presidential candidate Mitt Romney's father who during the 1950’s, was Chairman and President of the American Motors corporation. "I don't think he [Romney] is a bad guy. I'm sure he grew up loving cars as much as I did. But what I don't understand, what I don't think he understood, I don't think he understood that saving the automobile worker, saving the industry, what it meant to all of America, not just autoworkers. I think he saw it in terms of balance sheets and write-offs."

The next point Biden made was about the former Al-Qaida leader Osama bin Laden, depicting Obama's moment of decision on the raid to Abbotabad, and comparing between Romney's opinion that focusing on the search for one man is "naive"- and Obama's resolute. "Barack understood that the search for bin Laden was about a lot more than taking a monstrous leader off the battlefield. It was about so much more than that. It was about righting an unspeakable wrong. It was about healing an unbearable wound, a nearly unbearable wound in America's heart. He also knew the message we had to send around the world: If you attack innocent Americans, we will follow you to the end of the earth."

(At this point, Democrats proved that not only Republicans know how to chant "U-S-A! U-S-A!")

He attacked Romney and Ryan on their Medicare plan and budget cuts, and finished with praising the American people and their dealing with crisis. "Four years ago we were hit hard. But what did you do as Americans? What you've always done. You didn't lose faith. You fought back. You didn't give up - you got up. You never quit on America. And you deserve a president who will never quit on you. America is not in decline. I've got news for Governor Romney and Congressman Ryan: Gentlemen it's never been a good bet to bet against the American people. My fellow Americans, America is coming back. And we're not going back. And we have no intention of downsizing the American dream."