"If we do everything right, if we do it with absolute certainty, there's still a 30 percent chance we're going to get it wrong." – Joe Biden, in Feb. 2009, discussing the economic stimulus package with House Democrats.

"Under three [hours] I think, you know, high twos, about two hours and 50-something." – Paul Ryan, in Aug. 2012, answering a radio host who asked his "personal best" time in running a marathon. [Ryan’s actual time: 4 hours, one minute.]

WASHINGTON – In this corner, a 69-year-old, 6-foot heavyweight debater with an undisputed record of gaffes. In the opposite corner, a 42-year old, 6-foot-2 challenger with a powerful right-wing punch and some fancy footwork of exaggerations.

Plenty of plot lines could emerge from Thursday night’s pressure-packed debate between the Delaware Dandy, Vice President Joe Biden, and his young-Turk Republican opponent, the Wisconsin Wonk Paul Ryan, chairman of the House Budget Committee.

Their confrontation could end up as the Duel in Danville – a debate between two controversial but entertaining politicians a week after the Denver clash at the top of the tickets unexpectedly changed the trajectory of the campaign between President Barack Obama and Republican challenger Mitt Romney.

Obama’s defensive performance at the debate – and the narrowing of the national polls since then – has put more pressure on Biden to come out swinging when he faces Ryan, whose budget plan has become a favorite target of Democrats. Ryan, R-Wisc., told an interviewer that he expects Biden to fire at him like “a cannon ball.”

Viewers will see if the verbal barrages – from either side -- hit their marks and how well their defenses fend off challenges. The moderator, veteran ABC News correspondent Martha Raddatz, should be a factor in when and how zingers are fired, and how much time Biden and Ryan have to deflect them.

Most debates are decided on more subtle grounds, and a range of analysts and politicians will be scrutinizing the two men’s debate performances to see if they fit into any of the stereotypes that follow them into the hall at Centre College in Danville, Ky. Here are a few of the possible story lines.

The Serial Exaggerator vs. the Gaffe Machine

Judging from his marathon comment and a few other statements, critics charge that Ryan has a tendency to exaggerate – and Democrats are not letting him forget it.

After the marathon claim was debunked in August, a liberal scribe wrote: “Paul Ryan once made minute rice in 12 seconds.” Another Democrat devised a “Ryan calculator” that automatically shortens any marathon time that’s entered.

No doubt that debate analysts will be scrutinizing Ryan’s responses for exaggerations, just as they’ll be on the alert for any “Bidenisms” from the vice president. [Biden's gaffes are chronicled on several websites, including this one.]

In his most recent gaffe, Biden said forcefully that the middle class “has been buried the last four years.” Not exactly a perfect argument for re-electing Obama/Biden.

Earlier this summer, Biden told a mostly African-American audience that – by seeking to “unchain” Wall Street – Romney and Ryan are “going to put y'all back in chains.”

Biden hasn’t been appearing at many high-profile settings since then.

The Young Turk (age 42) vs. the 'Greedy Geezer' (age 69)

The fact that Biden is nearly 28 years older than Ryan could cut in either direction, depending on the trajectory of the debate. Biden’s seasoning and knowledge of Senate issues could help him, but Ryan’s relative youth might help him appeal to younger voters.

There’s no doubt that Biden is the more experienced debater – having survived a series of verbal slugfests stretching back four decades. And he does not usually make gaffes when he is in high-pressure situations, such as debates.

When he debated Sarah Palin four years ago, for example, Biden was careful in his comments and was credited by some observers as winning the confrontation.

In the earlier debates with Obama, Hillary Clinton and other opponents during the 2008 Democratic primary season, Biden at times displayed a biting sense of humor. At one point, he quipped about former New York Mayor Rudy Giuliani: “There’s only three things he mentions in a sentence: a noun, a verb, and 9/11.”

(The Huffington Post has assembled some of Biden’s better debate moments.)

Trying to lower debate expectations of Ryan, Romney said Tuesday that Biden was the more seasoned debater: “Obviously, the vice president has done, I don't know, 15 or 20 debates during his lifetime – experienced debater,” Romney told CNN.

“This is, I think, Paul's [Ryan’s] first debate. I may be wrong. He may have done something in high school, I don't know,” Romney said.

But that turned out to be a Ryanesque exaggeration; a Ryan spokesman said later that his boss had “done several [debates] over the years” in various congressional races.

Medicare iconoclast vs. Medicare-eligible defender

The generational gap between Medicare recipients and young people paying into the health-care system for the elderly is likely to be spotlighted in the debate.

As chairman of the House Budget Committee, Ryan is widely known for his budget plan, which – among many other things – would revamp Medicare in the future so it would be a voucher program, providing federal health insurance subsidies for retirees (starting with those now under age 55) so they can buy private insurance rather than enroll in Medicare.

An amended version of Ryan's plan also would allow retirees to choose a plan similar to today’s Medicare, although they would likely have to pay extra for it.

While’s Romney’s budget and tax plan differs in some ways from the Ryan plan – and seems to be morphing as his campaign pivots more toward the center – some of Biden’s “cannonball” artillery no doubt will be aimed at Ryan's Medicare proposal, as well as his refusal to increase taxes on the wealthy.

Ryan, who is a whiz at budget numbers, will be quick to respond. He gave a hint to his ammunition during his acceptance speech at the GOP convention in Tampa, when he claimed that the Affordable Care Act – which Obama and Biden championed – is in reality more damaging to Medicare, seeking $700 billion in cost savings from it.

"The greatest threat to Medicare is Obamacare, and we're going to stop it," Ryan told delegates. “A Romney-Ryan administration will protect and strengthen Medicare, for my Mom’s generation, for my generation, and for my kids and yours.”

The defense of the current Medicare system by Biden – who is old enough to be covered by the plan – is likely to reflect a generational difference in how Americans view the future of health insurance for the elderly. In fact, Biden is old enough to remember the days before Medicare, which was signed into law in 1965.

The Newbie vs. the Sage on Foreign Policy

As a former chairman (and longtime member) of the Senate Foreign Relations Committee, Biden has considerable experience in foreign policy and security issues. In theory, that should give him an advantage in debating Ryan, who has focused more on budget and other domestic issues during his tenure in the U.S. House.

But Ryan, who has been studying foreign policy issues in preparing for the debate, is likely to challenge Biden – a leading figure in overseeing the withdrawal of U.S. forces from Iraq during Obama’s administration – on some of his positions over the years.

For example, Biden opposed the 1991 Gulf War, which Republicans viewed as a big success. Biden voted in favor of the Iraq War resolution in 2002 (as did Ryan), but he later proposed Senate resolutions to alter U.S. strategy there and was hesitant about the “surge,” which military strategists credit with (temporarily) blocking insurgents in Iraq.

Ryan may go after what he views as inconsistencies on Biden’s Iraq record, and is likely to carry the flag for the Romney campaign’s foreign policy stance, which emphasizes “peace through strength” by resisting cuts to the U.S. military and taking more of a leadership role in the world.

Biden also led the Senate Judiciary Committee back in the 1980s and early '90s, incurring the wrath of conservatives when he chaired the contentious (and, at times, controversial) hearings of U.S. Supreme Court nominees Clarence Thomas and Robert Bork. From his days on Judiciary, Biden is knowledgeable on issues related to crime prevention, civil liberties, drug policy, and violence against women.

The wonky Cheesehead vs. the Wilmington brawler

Both Biden and Ryan have been trained in attack-dog tactics as vice presidential candidates, and both men are likely to go on the offensive during the debates. But Ryan tends to be wonky in his attacks, while Biden is more of a brawler.

During the 2008 campaign, Biden honed what often proved to be an effective offense against GOP presidential candidate Sen. John McCain, R-Ariz., and his running mate, former Alaska Gov. Sarah Palin. But Romney-Ryan may prove to be a more difficult target, in part because few would question Ryan’s expertise on some national issues.

“Because of the president's terrible performance, because Mitt Romney did such a good job of giving the country a choice, they don't have a choice but to have Joe Biden come at me," Ryan told a Milwaukee radio station this weekend.

And Biden hinted as much during his last campaign swing in Florida at the end of September. The vice president blasted Ryan and Romney for insisting on tax cuts for the super wealthy and rejecting bipartisan plans to reduce the federal deficit.

Noting that Ryan had voted against the recommendations of the Simpson-Bowles deficit-reduction commission in 2010, Biden told supporters in Florida:

Ryan “wouldn’t even vote to let it get to [Congress] to vote on it. Why?” Biden demanded. “Because they will not vote for a single solitary reduction in the debt if it includes $1 in new taxes for millionaires. Not even $1. That’s a fact.”

For stories about the issues and candidates in this election from St. Louis Public Radio, the Nine Network and the St. Louis Beacon, visit BeyondNovember.org. For a collection of Beacon stories, visit our 2012 election page.