Joe Biden and Paul Ryan clashed repeatedly in a fast-paced and contentious debate on Thursday night, with the vice president more aggressively interrupting and dismissing his fact-filled opponent.

The Kentucky faceoff was a clash of generational styles, Biden the sometimes exasperated lecturer, Ryan the serious-minded student. Biden proved the superior debater, raising his voice, directly addressing the audience and rising above the wonky arguments with greater effectiveness. But by going toe to toe against a graying incumbent, the Wisconsin congressman held his own and blunted some, but not all, of his rival’s attacks.

Biden showed considerable passion when the debate turned to the economy, getting in more attack lines in two minutes than President Obama did against Mitt Romney in an hour and a half: Romney wanted to let Detroit go bankrupt. Romney wrote off 47 percent of the country. Romney pays a lower effective tax rate than Biden’s parents and neighbors.

Ryan was rather flat in response, ticking off a five-point economic plan, then lurching into a tale about Romney financially aiding a family whose four kids were killed in a car crash—touching, perhaps, but a total non sequitur. That, however, prompted Biden to recall the 1972 car accident that killed his wife and daughter, as if he had to match the emotional card that Ryan had thrown down.

Ryan’s best line was an attempt to defuse Romney’s fundraising comments about the 47 percent of Americans who pay no federal income taxes: “I think the vice president knows, sometimes words don’t come out of your mouth the right way.” Biden had to smile.

They each spewed numbers about Medicare, with Ryan accusing Democratic critics of trying to “scare people” about a plan that would give future retirees a choice, including vouchers. He also accused the administration of turning Medicare “into a piggy bank for Obamacare.”

That’s when Biden started speaking to the camera, saying the Ryan vouchers would cost the average senior citizen $6,400 a year, according to the Congressional Budget Office. He touted higher prescription drug benefits for seniors as well. “Folks, who do you trust on this?” Biden asked.

When the talk turned to taxes, Biden ripped the Republicans for pushing to extend the Bush tax cuts for the wealthy, saying “they’re holding hostage the middle-class tax cut to the superwealthy,” calling this “unconscionable.” Ryan responded by saying the administration would raise the effective tax rate on small businesses to more than 40 percent and that he and Romney would cut taxes for everyone without hurting the middle class.

“Not mathematically possible,” Biden interrupted.

“It is mathetmatically possible,” Ryan insisted.

Biden took the fight to Ryan in the opening minutes, interrupting his indictment about “the unraveling of the Obama foreign policy” by saying—with “all due respect,” of course—“that’s a bunch of malarkey.” He landed a jab as Ryan was decrying the fatal attack on the U.S. consulate in Libya by saying that his opponent’s House budget cut embassy security $300 million below what the administration had requested.

The vice president had finessed a tough question about the attack from moderator Martha Raddatz by promising that any “mistakes” would not be repeated and quickly pivoting to the successful mission against Osama bin Laden. Ryan scored a moment later by saying “it took the president two weeks to acknowledge that this was a terrorist attack.”

Ryan remained on offense by charging that the administration “has no credibility” on Iran, which he said in “racing toward a nuclear weapon.”

“Incredible,” Biden said with a laugh, dismissing the “bluster” about Iran and saying Obama had imposed “the most crippling sanctions” in history.

Ryan tried to seize the initiative, even ripping President Obama for going on The View rather than meeting with Bibi Netanyahu—and Biden counterpunched, sometimes with derision. In short, he did precisely what his boss failed to do against Romney.

The discussion of Afghanistan was a wash, with Ryan conceding that his ticket supports Obama’s plan to withdraw U.S. troops by 2014 and, when pressed by Raddatz, acknowledging: “We don’t want to stay.”

The debate may have served as a preview of 2016, with Biden not ruling out a run for the top job and Ryan considered a contender if Romney loses.

The debate wound toward a close on a solemn note, with Raddatz asking the candidates about the role of their Catholic faith in their views on abortion. Ryan said he believes the church’s teaching that life begins at conception, and that a Romney administration would oppose abortion except in cases of rape, incest and the life of the mother.

Biden said he too accepts the church’s position on abortion, “but I refuse to impose it on equally devout Christians, Muslims and Jews.” He also noted, correctly, that Ryan has opposed the exceptions for rape and incest, and that Romney would appoint Supreme Court justices who would overturn Roe v. Wade —an important part of the Democrats’ appeal to women.

The pressure heading into the Danville event was largely on Biden, in large measure because Obama, by his own admission, had “a bad night” at the first debate. With the president having failed to challenge Romney’s agenda, the task fell to his running mate to do so—and without seeming overbearing or condescending.

There was also lots of pregame chatter that the voluble Biden might be gaffe-prone, which managed to overlook his history as an experienced debater.

Ryan, who has never played on the national stage, faced lower expectations, which mainly involved defending Romney on his embrace of the congressman’s budget-slashing and Medicare reform plans. As the House Budget Committee chairman, Ryan is practiced in facts-and-figures discussions but not at playing to a television audience.

In the end, few vice-presidential debates matter much. One exception may have been when Sarah Palin held her own against Biden four years ago, quieting, at least temporarily, doubts about her candidacy. But the main function of the running mates in their single encounter is to serve as surrogates for the top of the ticket, and both men did that effectively on Thursday night.