At 9 p.m. tonight, The Washington Post will stream the vice presidential debate live on the Grid. The live video experience is complemented by the social conversation below – tweets, analysis and more context from Post reporters as the candidates square off.

The Washington Post’s Felicia Sonmez and David Farenthold reported today on the scene ahead of the debate in Danville, Ky., and Joe Biden and Paul Ryan’s preparation for it:

Vice President Biden and Rep. Paul Ryan will square off Thursday night in this year’s lone vice presidential debate, playing roles that few would have expected two weeks ago.

For Ryan, the job is to keep up a sudden surge of Republican momentum. For Biden, by contrast, the job is to find any way of stopping it.

The debate will begin at 9 p.m. at Centre College in Danville. It will feature two Washington veterans with sharply different styles. Biden is often emotional and personal, making points with anecdotes instead of numbers. Ryan, the House Budget committee chairman, seems to think at a higher and more removed elevation: he stresses trend lines, disasters a few decades out.

Neither has faced a debate quite like this one. In 2008, Biden had a much different opponent in then-Alaska Gov. Sarah Palin (R), who had little experience in national politics.

Both men have spent weeks preparing for these 90 minutes. Ryan did at least three rehearsals, then spent days in a “debate camp” in Virginia. Biden’s aides went so far as to construct a mockup of the debate set for the vice president’s practice sessions in Wilmington, Del., according to a CNN report.

Both men did private walk-throughs on the real debate set Thursday. As the hours ticked down, the two camps discussed their strategies only in the flat platitudes that are traditional at such moments.

Earlier, David Farenthold outlined the number one rule for the contenders: Don’t let the spotlight land on them. Instead, people should be talking about their running mates at the top of the ticket tomorrow morning:

The dark art of the vice presidential debate begins with a single rule: If everybody’s talking about you, you’re doing it wrong.

Since 1976, there have been eight televised face-offs between vice presidential nominees. By now, both parties have worked out tactics for this odd ritual. They require the barbed wit of an insult comedian and the humility of the hind legs in a two-man horse costume.

Candidates are told: Talk up your running mate. Zing your opponent. But avoid letting your career or your policy ideas become the focus. On the biggest night of your political life, it’s not about you.

On Thursday, the stakes will be unusually high, and the job of playing second banana especially tough. Biden spent 36 years in the Senate. Ryan crafted a plan for remaking the entire government.

Now, these proud, successful men will have to insist — convincingly — that they’d rather talk about somebody else.

“Whatever you stood for, you stand for the team” now, said Samuel Popkin, a professor at the University of California at San Diego who has helped coach Democrats in debates. Popkin said the task might be especially touchy for Ryan, because Romney has said he would not adopt Ryan’s famous budget plan in full.

“You need his goal in life to be power now, not power later,” Popkin said. “The only way I can see you do that is to get Ryan to say, ‘Romney’s budget is better than what I started with.’ ”

Conservative news outlets raised issue with the role of VP debate moderator Martha Raddatz, since her ex-husband is a friend of the president’s. She the People blogger and columnist Melinda Hennberger took issue with the complaint:

“Apparently, ABC’s senior foreign correspondent, Martha Raddatz, has no business moderating tonight’s vice presidential debate because the boss of one of the men she’ll be grilling attended the 1991 wedding of a guy she divorced 15 years ago. Got it?

“I don’t: Some conservatives have questioned her ability to be objective about Joe Biden, given that Barack Obama is close to her first husband. But why on earth should someone so qualified be penalized because the law school pal of her ex, Julius Genachowski, who now runs the Federal Communications Commission, grew up to become president?

“Others feel that she and ABC should at a minimum have disclosed such a potential conflict, but wouldn’t that have sounded more like a third-rate brag? (Sort of like, just for instance, Disclosure: At the recent Republican National Convention in Tampa, I had not one but two pleasant airport chats with Tucker Carlson, founder of the Daily Caller, the outlet that brought this non-news to the world’s attention. And?) …

“My friend Jeff Weiss thinks that as a buddy of someone Raddatz used to love, it’s just as likely that she has in for Obama, though I think that’s a stretch, too; I can’t imagine either favoring or holding a grudge against someone on that basis, can you?

“Here’s the thing: As the Daily Beast’s Howard Kurtz notes, Raddatz knows her foreign policy potatoes, having “been to Iraq 21 times and traveled to Afghanistan and Pakistan dozens of times. She has also covered the White House and the State Department. Raddatz was the first to report that Abu Musab al-Zarqawi, al-Qaeda’s leader in Iraq, had been killed in a U.S. airstrike, and reported exclusive details the night that Osama bin Laden was killed.”