The pressure is on for the VP debate

While the vice presidential debate is normally a side show, this one on Thursday has the potential to be a major event, not only because of the president's poor performance in his first debate last week, but because of the contrasts between the two candidates.

Vice President Joe Biden said recently: "All debates are tough."

GOP vice presidential candidate Paul Ryan took a lighter tone, joking with an audience: "What debate? Oh yeah! I'd better get ready for that."

The debate will pit age against youth, a "Great Society" liberal against a Tea Party conservative.

Biden became a U.S. senator when Ryan turned 3, and ran for president twice. He's been on many debate stages before.

"There's nothing like standing up before 20, 30, 40, 50, 60, 70 million people, you know?" Biden told a crowd recently.

But he's also a non-stop talker prone to putting his foot in his mouth, which Ryan could exploit, as he did last week.

"Vice President Biden just today said that the middle class over the last four years has been, quote, 'buried.' We agree!" Ryan said, trying to capitalize on a Biden gaffe.

On "Face the Nation" on Sunday there was no shortage of debate advice for both men.

"I think Paul Ryan has to address some specific questions about his budget plan, but he also has to make it clear that it is his budget plan. Mitt Romney's plan is the one that is going to be implemented in the White House," said John Fund, senior editor for The American Spectator.

"Biden is going to have to be aggressive in this debate. That is not an easy thing to calibrate, you can go overboard here and he is opposing a young, earnest guy that is like a Boy Scout," said Michael Gerson, a former speechwriter for George W. Bush.

Many Democrats think the president's showing last week won't change the trajectory of the race much. That could change, of course, if Vice President Biden is also perceived to lose his debate. Some fear that could be a real problem.