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.

The Stakes

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.

Their Liabilities

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.

Their Strengths

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.

The Format

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."

Also on HuffPost:

Loading Slideshow...
  • 'The Stumble'

    Texas Governor Rick Perry's <a href="http://www.huffingtonpost.com/2011/11/09/rick-pery-forgets-federal-agencies_n_1085312.html" target="_hplink">inability to remember</a> the third agency he would cut as president had many predicting the untimely end of his campaign for president. Perry addressed his mental lapse before reporters after the debate, admitting, "Yeah I stepped in it man. Yeah it was embarrassing. Of course it was."

  • Romney's '$10,000 Bet'

    During a GOP primary debate in late 2011, Romney sought to put an end to then-presidential candidate Rick Perry's insistance that Romneycare was the basis of President Barack Obama's health care reform law. Perry launched in with an attack that he'd repeated before: "I'm just saying, you're for individual mandates, my friend," Perry said. "You've raised that before, Rick, and you're simply wrong," Romney responded, extending his hand toward Perry. "Rick, I'll tell you what: 10,000 bucks? $10,000 bet?" Perry declined, nothing that he wasn't a betting man, leaving Romney to quote a chapter from his book that he cited as proof he had never intended for his health care plan to be used as a national model.

  • Bachmann On Libya, Africa

    At a GOP primary debate in October of 2011, Michele Bachmann (R-Minn.) <a href="http://www.huffingtonpost.com/2011/10/18/michele-bachmann-libya-africa_n_1018814.html" target="_hplink">criticized</a> Obama's foreign policy decisions. "Now with the president, he put us in Libya," she said. "He is now putting us in Africa. We already were stretched too thin, and he put our special operations forces in Africa." Libya is, in fact, a country in Africa.

  • Awkward Silence

    During a 2010 gubernatorial debate, Arizona Governor Jan Brewer <a href="http://www.huffingtonpost.com/2010/09/02/jan-brewer-starts-badly-f_n_703559.html" target="_hplink">struggled to name</a> any of her accomplishments while introducing herself. "We have ... done so much ... We have um, did what was right for Arizona," she squeezed out after a long silent pause.

  • Can't Name Any Supreme Court Cases

    Christine O'Donnell was unable to name a single recent Supreme Court decision she disagreed with, when asked by moderator Nancy Karibjanian during a 2010 Delaware Senate debate. <a href="http://www.huffingtonpost.com/2010/10/13/christine-odonnell-stumped-supreme-court-debate_n_762067.html" target="_hplink">The dialogue</a>: <blockquote><strong>KARIBJANIAN</strong>: What opinions, of late, that have come from our high court, do you most object to? <strong>O'DONNELL</strong>: Oh, gosh. Um, give me a specific one. I'm sorry. <strong>KARIBJANIAN</strong>: Actually, I can't, because I need you to tell me which ones you object to. <strong>O'DONNELL</strong>: Um, I'm very sorry, right off the top of my head, I know that there are a lot, but I'll put it up on my website, I promise you.</blockquote>

  • Can I Call You Joe?

    When Sarah Palin and Joe Biden shook hands at the start of a 2008 vice presidential debate, Palin asked then then-Senator "Hey, Can I call you Joe?" "You can call me Joe," Biden replied. Palin <a href="http://www.politico.com/blogs/bensmith/0110/Two_versions_of_Can_I_call_you_Joe.html" target="_hplink">evidently kept confusing</a> then-Senator Joe Biden's last name with President Barack Obama's, referring to the VP candidate repeatedly as "O'Biden" in debate prep. Her staffers suggested she call him by his first name.

  • Change You Can Xerox

    Hilary Clinton's attempt at a jab toward President Barack Obama got her booed by the audience during a 2008 presidential debate. Clinton accused Obama of plagiarism in his popular speeches, saying "Lifting whole passages from someone else's speeches is not change you can believe in, it's change you can Xerox."

  • 'Likable Enough'

    During a Democratic presidential primary debate in early 2008, then-candidate Hillary Clinton was being pressed on surveys that suggested New Hampshire voters appreciated her resume, but found then-Sen. Barack Obama (D-Ill.) more likable. Clinton appeared to feign insult, drawing sympathetic applause and smiles from the crowd. "Well, that hurts my feelings," she said. "But I'll try to go on. "He's very likable," Clinton continued of Obama. "I agree with that. I don't think I'm that bad." Obama took a brief break from scribbling notes to weigh in. "You're likable enough, Hillary," Obama said tersely, not making eye contact with Clinton. He then returned to his notepad.

  • Al Gore's Sighing

    A 2000 presidential debate seriously hurt Al Gore's campaign when the cutaway shots caught him rolling his eyes and sighing audibly during George W. Bush's answers. Critics say behavior made Gore look elitist and unlikable in contrast with Bush's relaxed and folksy demeanor. Jon Stewart mocks Gore's sighs in The Daily Show clip above.

  • Let Me Finish

    Ross Perot may go down in history for his repeated interruptions of "let me finish" during a 1992 presidential debate. The behavior became fodder for SNL comedian Dana Carvey's Perot impression.

  • Glancing At His Watch

    George H. W. Bush was caught glancing at his watch during a 1992 presidential debate with Bill Clinton and Ross Perot. The now-famous move damaged Bush's campaign, making him look bored and impatient, <a href="http://www.usnews.com/news/politics/articles/2008/01/17/a-damaging-impatience" target="_hplink">reports say</a>. Bush snuck at peek at his watch again during his daughter-in-law Laura Bush's speech at the Republican convention in 2008.

  • Who Am I? Why Am I Here?

    When Independent Presidential candidate Ross Perot picked Vietnam War hero Admiral James Stockdale for his VP nominee, it created a rare three-person Vice Presidential debate in 1992. Stockdale was not a politician and not very well known. Attempting to introduce itself and poke some fun at this, he chose as his opening statement: "Who am I? Why am I here?" Stockdale later said he hoped to follow up the remarks with an explanation of his life, but never got to that point. Instead, the line left viewers wondering the same thing.

  • Dispassionate Death Penalty Response

    When the moderator of a 1988 presidential debate asked Governor Michael Dukakis if he would support the death penalty if his wife, Kitty Dukakis, was raped and murdered, Dukakis dispassionately responded, "No, I don't, Bernard, and I think you know that I've opposed the death penalty during all of my life." He then continued to talk about his stance. Some believe the lack of emotion or passion for the hypothetical situation cost Dukakis the election.

  • You're No Jack Kennedy

    In the 1988 Vice Presidential debate between Democratic VP candidate Senator Lloyd Bentsen and Republican VP candidate Senator Dan Quayle, Quayle was asked if his qualifications were sufficient to inherit the presidency, should it come to that. Quayle responded by comparing his experience level Jack Kennedy's experience level when he sought the presidency. The comparison prompted Bensten to say: "Senator, I served with Jack Kennedy. I knew Jack Kennedy. Jack Kennedy was a friend of mine. Senator, you're no Jack Kennedy." Quayle responded, "That was really uncalled for Senator."

  • No Soviet Domination

    In the 1976 presidential debate between Jimmy Carter and Gerald Ford, Ford famously stated "There is no Soviet domination of Eastern Europe." The remark came in response to a question about U.S. relations with the Soviet Union, a major concern in the Cold War era, and didn't sit well with an increasingly anti-Soviet public. Ford refused to back down from the claim even after the somewhat baffled debate moderator responded, "I'm sorry, what? ... Did I understand you to say, sir, that the Russians are not using Eastern Europe as their own sphere of influence in occupying most of the countries there and making sure with their troops that it's a communist zone?"

  • Sickly Nixon vs. Fit JFK

    The 1960 presidential debate between John F. Kennedy and Richard Nixon was the first nationally televised debate in the U.S. and <a href="http://www.time.com/time/nation/article/0,8599,2021078,00.html" target="_hplink">is thought to have</a> changed politics forever. The debate was historically declared a win for Kennedy by those who watched it on TV, and a win for Nixon for those who listened to it on the radio. Though the candidates were both strong on the issues, the visibly sweating Nixon looked sickly and pale compared to the young and fit Kennedy.