An aggressive Vice President Joe Biden went after Rep. Paul Ryan on the economy, taxes, foreign policy and more throughout their 90-minute debate in Danville, Ky., on Thursday night.  

Frequently scoffing and smiling at Ryan's claims, Biden several times explicitly cast doubt on the GOPer's veracity and command of the facts. 

Unprovoked, Biden brought up Mitt Romney's devastating 47% remarks, in which the White House hopeful dismissed nearly half of the electorate as government moochers—and which President Obama failed to mention in his own debate last week.

"It shouldn't be surprising for a guy who says 47% of the American people are unwilling to take responsibility of their own lives," said Biden. "My friend [Paul Ryan] recently said in a speech in Washington said 30% of the American people are takers. These people are my mom and dad, the people I grew up with, my neighbors. They pay more effective tax than Gov. Romney pays in his federal income tax. They are elderly people who in fact are living off of Social Security. They are veterans who are fighting in Afghanistan right now who are not quote, not paying taxes."

WATCH THE CLIP ABOVE OF BIDEN'S 47% ATTACK

That testified to a combative approach throughout from the vice president, who, in a likely successful effort to re-enthuse Democrats after Obama's limp performance last week, repeatedly sought to challenge Ryan on everything from social programs to jobs to national security.

Of course, Ryan got a zinger of his own in when he referred to the interruption-laden debate.

"I know you're under a lot of duress to make up for lost ground, but I think people would be better served if we don't interrupt each other," Ryan said, referring to President Obama's poor debate performance last week.

The high-stakes faceoff kicked off with a discussion of the deadly attacks at the U.S. consulate in Benghazi, Libya, with Ryan criticizing Obama's initial unwillingness to call the violence terrorism.

Biden promised to pursue the attackers, and vowed that any mistakes in the original assessment of the attack would "not be made again." He also ripped Ryan for not laying out a clear plan on foreign policy.

At one point, Biden declared that Ryan was full of "malarkey" after the Republican accused the president of advocating "devastating defense cuts."

The two also traded blows on Iran, with Ryan insisting the U.S. was failing to stop Iran from acquiring a nuclear weapon. Biden countered by insisting that his team has implemented the "most crippling sanctions in the history of sanctions."

The debate got personal —and serious—when moderator Martha Raddatz of ABC News asked the two candidates how their Catholic faith has played into their personal views on abortion.

Biden said his religion teaches him that life begins at conception, but would not impose his beliefs on all Americans. "I do not believe we have the right to tell people, women, they can't control their body," the former Delaware senator said.

Ryan said he is against abortion, but would include exceptions in cases of incest, rape or when the life of the mother is at risk. 

One of the night's most memorable lines came during a discussion of tax policy. Ryan insisted that Mitt Romney could make good on his promises to lower tax rates without increasing the deficit.

"Not mathematically possible," Biden quipped. "It is mathematically possible," Ryan insisted. "Jack Kennedy lowered taxes and raised revenue."

Biden shot back, "Oh, now you're Jack Kennedy?" That evoked memories of the famous moment in the 1988 vice presidential debate in which Lloyd Bentsen schooled Dan Quayle. After Quayle brought up JFK, Bentsen replied: "Senator, I served with Jack Kennedy, I knew Jack Kennedy, Jack Kennedy was a friend of mine. Senator, you're no Jack Kennedy."