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New Jersey Gov. Chris Christie accused President Obama of lying this morning after I showed him an advertisement being run by the Obama campaign attacking Mitt Romney's economic plan and accusing the former Massachusetts governor of wanting to cut taxes for the wealthy. I asked Christie how he would respond if it were him debating the president Wednesday night during the first presidential debate.

"Stop lying, Mr. President…Governor Romney is not talking about more tax cuts for the wealthy. In fact, what he said is that the wealthy will pay just as much under a Romney administration as they pay today," Christie said on "This Week." "I love those ads. I mean, you know, the president gets to say things like a million new manufacturing jobs, well, how, Mr. President? We're still waiting. Four trillion reduction in the debt. Really, Mr. President? How? Simpson-Bowles? You haven't endorsed your own plan. Nor has he come forward with a plan. I mean, it's a great ad. I have no doubt about that. It sounds really nice, and it looks nice. But there's nothing substantive there."

President Obama released an advertisement last week that accused GOP presidential nominee Mitt Romney of sticking with policies that led to the financial crisis in 2008.

"Governor Romney believes that with even bigger tax cuts for the wealthy, and fewer regulations on Wall Street, all of us will prosper. In other words, he'd double down on the same trickle down policies that led to the crisis in the first place," Obama said in the two minute advertisement.

I spoke with White House senior adviser David Plouffe after my interview with the governor of New Jersey and he called the accusation that the president was lying, "not true."

"Strong words and not true. Listen, analysts have looked at this. Someone who makes over $3 million a year would get over a $250,000 tax cut if Governor Romney's plan were to be enacted. And let's just step back. It's a $5 trillion tax cut, $2 trillion in defense spending, by the way, that our Pentagon and our military leadership says we don't know, another $1 trillion to extend all the Bush tax cuts. That's $8 trillion," Plouffe said. "The notion that somehow by closing loopholes for the wealthy that the middle class is going to be held harmless - you know, the middle class needs to understand, if - if Mitt Romney wins this presidential election, they're going to be paying the bill, not to reduce the deficit, not to reduce jobs, but to give huge tax cuts to the wealthy," he said.

"So we're happy to have that debate, because we think the facts are on our side," Plouffe said.

I also asked Christie if Romney would shake things up on Wednesday and the New Jersey governor told me that the debate would be a positive turning point for Romney.

"I mean, every time Mitt Romney has been confronted in this campaign with one of these moments, he has come through in the debate and performed extraordinarily well, laying out his vision very clearly, and also contrasting himself and his vision with whoever his opponent was at that time," Christie said. "So I have absolute confidence that, when we get to Thursday morning, George, all you're going to be shaking your head, saying it's a brand-new race with 33 days to go. "

For his part, Plouffe said Romney has more to gain from the debate and added that the president would lay out his plan for the next four years.

"We believed all along that Governor Romney probably has more benefit out of this debate potentially than we do," said Plouffe. "But what we're going to tell the American people on Wednesday night, as we have through the whole campaign, is exactly where we are as a country, where we need to go, how we rebuild an economy that makes the middle class secure, and with great detail so people understand, when - if this president gets re-elected, what he's going to do for them, for the middle class, in the next four years," he said.

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