WASHINGTON -- Vice President Joe Biden and Rep. Paul Ryan (R-Wis.), Mitt Romney's running mate, only get one shot at each other.
They'll face off at Centre College in Danville, Ky., on Thursday night. Here's a look at the stakes, the strengths and liabilities for each man, the debate format and what to look for.
A clear win for Biden will arrest some of the positive momentum that the Republican ticket of Romney and Ryan is enjoying right now. Much of the impact will be in and through the media. If Biden is able to emerge with a victory, it will calm down some of the hyperventilating among liberals who have engaged in an Andrew Sullivan-led freakout for much of the past week, following President Obama's weak debate performance in Denver.
How much a Biden win would impact actual voters would depend on how resoundingly he beat Ryan -- which would in turn dictate the degree to which the media emphasized a possible shift in momentum -- and on how many people tuned in. Biden's debate with former Alaska Gov. Sarah Palin (R) four years ago was watched by 70 million people -- as many as watched Romney and Obama last week, but the 2008 viewership shattered records for vice presidential debates. Going back to the first veep debate in 1976 between Republican Bob Dole and Democrat Walter Mondale, the lowest ratings were about 30 million and the highest were around 50 million.
A clear win for Ryan, on the other hand, would probably accelerate the current dynamic, with Romney gaining in the polls, Republicans growing more enthusiastic, Democrats becoming more anxious and media coverage portraying Romney as surging. If Ryan were to win, it would likely be on the basis of a policy-heavy presentation, which could amplify the impression among voters that he and Romney are a team defined by capability.
In the event of unclear overall outcome, Biden will try to sow seeds of doubt about Ryan's preparation for the job, a subtle way of capitalizing on the 42-year-old's relative youth. Biden's biggest biographical vulnerability is that he has become known as a gaffe-prone goof ball, but there's no real incentive, and no clear way, for Ryan to attack that. Plus, Biden's public profile is well established, and could help Biden -- who at 69 years old is of course far more knowledgeable, experienced and savvy than his public caricature -- because expectations may be lower.
Ryan's main avenue for going on offense is probably on policy, where he is most knowledgeable. He likely doesn't have a choice. If he doesn't go on offense here, he will be on defense.
Ryan is a wonk. Biden is undisciplined.
Ryan will have to avoid going too heavy on data, numbers and arcane policy details. If he cannot resist it, he will risk losing a large chunk of his audience. It's possible that some voters may see him as a policy wizard and like that, but Ryan can also come across like he's lecturing sometimes.
Ryan's other glaring vulnerability is on foreign policy. Even if he has studied the briefing books and is up to speed on what is going on around the globe and in its many hot spots, he does not have Biden's experience and knowledge base. He will have to counter whenever Biden tries to emphasize this difference in gravitas.
Biden, of course, will have to guard against letting his mouth get ahead of him. But the vice president's ability to restrain himself may be underestimated. The real question for Biden, when it comes to discipline, is whether he's worked hard enough to master not only the details of budget and tax policy, but also to know where Ryan is going to go on these issues. If he has, and is prepared with substantive, well thought-through counter answers, he could gain an edge.
On the other hand, Ryan has the capability to run circles around most politicians when talking about tax policy, the budget, debt and deficits, entitlements and health care.
"You can be sure that Paul Ryan knows his plan," said Rep. Chris Van Hollen, (D-Md.), who has battled with Ryan on the House Budget Committee for years, in a video released by the Obama campaign.
"After 14 years in the House, including six as the top Republican on the powerful House Budget Committee, he's been the face of the Republicans in articulating their policies," Van Hollen said. "He is seen as one of the most quick-on-his-feet elected officials in the country, and we know he doesn't back down in debates."
This is a bit of setting up expectations by Van Hollen in a way that he hopes will help Biden. But it's also accurate. Ryan not only knows the most complicated policy areas inside and out, he has had a lot of practice over the last few years in learning how to make the political sale for these ideas. That means you'll probably hear a lot of talk about a "prosperity agenda," a term that Ryan didn't use when he first rolled out his "Road Map" several years ago.
And despite his wonkiness, Ryan is a gifted politician with a regular guy appearance and an easy manner. He is a formidable foe.
Biden, of course, is a veteran pol. He served in the Senate for 36 years, so he has a far deeper knowledge base on domestic and foreign policy than he is given credit for. As mentioned before, he has real foreign policy experience, having had a major role in crafting the Obama administration's policy in Iraq, Afghanistan and Pakistan, and having taken many trips to meet with foreign leaders in those countries as well as others.
The fact that Biden is underestimated on domestic policy is an advantage. And he is from working-class roots. He knows how to talk to blue-collar independents and to conservative Democrats who might decide key states like Ohio. So his debate strategy may be to talk directly to these people as much as possible, keeping Ryan at bay on policy but avoiding too many direct, detailed engagements.
There is more time for each topic in this vice presidential debate than there was in 2008, when Biden and Palin had 90 seconds to respond to each question, with two minutes then for rebuttal and follow up.
Thursday night, Biden and Ryan will get two minutes each on a question, and then moderator Martha Raddatz, of ABC News, will let the two of them engage one another for four minutes and 15 seconds.
That means there is more time for Ryan to do mini-deep dives on policy, giving him a slight advantage if he can make use of it.
What To Watch For
Can either man corner the other on tax policy and entitlements? Ryan will make a detailed case but risks getting lost in the weeds. Biden will make a political case aimed at swaying middle-class voters but cannot rely solely on talking points.
Secondly, Biden's points of attack on Ryan will foreshadow how Obama himself will come after Romney next week. Look for how Biden frames Romney's tax plan and his Medicare plan. Biden will undoubtedly also go after Ryan on the issue of health insurance for those with preexisting conditions. But will he dredge up things that Romney said during the primary to drive the message that Romney is just faking moderation now? Obama adviser Robert Gibbs already did that once on NBC's "Meet the Press" Sunday, reading a Romney quote that directly stated that the now-GOP nominee would be cutting the marginal tax rate for all incomes, including "the top one percent."