At 9 p.m. tonight, The Washington Post will stream the 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 answer questions from voters in the town-hall style debate.

The Washington Post’s Scott Wilson wrote that the debate could once again shake up the race, as the first presidential debate did:

The stakes, as well as the level of uncertainty, surrounding their second encounter remained unusually high after a puzzling first debate performance by the president, a gifted speech maker who appeared flat-footed and defensive onstage with Romney nearly two weeks ago.

Since that evening in Denver, a race that had appeared to be Obama’s to lose has shifted in measurable ways toward Romney, as polls tighten nationally and in more than a half dozen states that will decide the election. Each candidate arrived in Hempstead, N.Y., about 25 miles east of New York City, with a different mission.

Obama, who has been preparing for several days in the relative seclusion of Williamsburg, Va., is looking to reassure an agitated Democratic base that he intends to defend his record and critique Romney’s policy proposals in a far more pointed way than he attempted to do in Denver.

“I feel fabulous,” Obama told reporters Tuesday morning before his departure from Williamsburg, a colonial-era town along the James River. “Look at this beautiful day.”

For Romney, another offensive-minded effort similar to his performance in Denver would help convince many of the voters who have given him a second look since then that his appeal is more than just the result of a bad night from the president.

Romney, who picked up deficit-hawk H. Ross Perot’s endorsement Tuesday, was sharp in the first debate. He unsettled the president, not least when he appeared to disavow his proposals for a broad tax cut should he win.

Obama said the former Massachusetts governor presented a false picture of his plans, but many swing voters in Ohio, Colorado, Florida and other key states have since moved Romney’s way.

Election 2012 blogger Rachel Weiner reported on the town hall debate’s format, which puts the voters Obama and Romney are trying to woo front and center, in contrast to the first debate:

There will be no opening (or closing) statements from President Obama and Mitt Romney; moderator Candy Crowley will introduce the candidates. Then town hall participants, undecided voters selected by the Gallup Organization, will start asking questions. Romney gets the first question. 

After each question, both candidates get two minutes to respond. Crowley will then ask a follow-up question. The candidates will have another two minutes total to discuss, but that time can be extended at Crowley’s discretion. The Presidential Debate Commission is hoping to get through 13 questions.

Both campaigns objected to Crowley’s intention to ask follow-up questions, having agreed themselves that she would not do so. But that agreement did not include Crowley or the commission.

Candy Crowley’s role has been a topic of some discussion this week, after it was reported that both campaigns joined together in saying she should not ask follow-up questions. The debate commission has confirmed, however, that she will be allowed to do so tonight. Here, The Fix laid out why it’s essential that a moderator back up the voters in the audience to press candidates on their pre-baked talking points:

 In all, there will be 82 town hall members on the stage. Only Crowley will know the questions in advance. The town hall participants have already submitted their questions to her. With a small team of helpers, she’s chosen the people who will get to speak and the order in which they will do so.

Do we understand why the campaigns want Crowley, one of the best political journalists in the business, to be seen but not heard? Absolutely. Is it an absolutely ridiculous request? Absolutely.

For anyone who wonders why, go back and think how many town halls politicians have held over the years and how many of them have yielded any news or genuine insight into the candidates or their positions. If that number isn’t zero, it’s darn close.

While we are all in favor of “regular” people getting to directly question the candidates, the simple fact is that the likelihood is that these questions will be broad rather than narrow — a reality that will allow Obama and Romney to stick with their pre-determined talking points. That means a news-less debate and less new information for voters still trying to make up their minds.

Moderators matter.  Journalism may not be the most popular profession these days but it is absolutely true that years of practice — like Crowley has had — trying to draw politicians out beyond their comfort zones is a skill.  Not everyone can do it. (Yes, we understand the self-interest in making this argument. A reporter defending the inherent value and unique talents of reporters. What a shock! But, simply because it’s self serving doesn’t mean it’s not true.)

Put another way: Does anyone doubt that last week’s debate between Vice President Joe Biden and Wisconsin Rep. Paul Ryan wasn’t improved — and made more edifying for the “regular” viewer — by moderator Martha Raddatz bringing her knowledge to the table and interjecting herself in the debate?

So what exactly do President Obama and Mitt Romney have to do to perform well? Obama’s challenge, The Fix writes, is to show more energy than his last outing, while Romney’s well-received performance in his first debate means higher expectations to live up to this time:

* Obama’s ‘porridge’ question: In the first debate, Obama was clearly too cool, seemingly disengaged from the proceedings and giving off an “I want to be somewhere else” vibe.  But, arguably, Joe Biden was too hot in the vice presidential debate — scoffing at, laughing at and generally ridiculing Wisconsin Rep. Paul Ryan throughout the proceedings. For Obama to “win” this debate, he has to find some middle ground between his own debate performance and that of his vice president, with a finger on the scale toward being too hot rather than too cold. The issue with that strategy is that — as we mentioned above — it’s not really who Obama is. He is the cool, cerebral politician, not the knife-fighting scrapper who grinds out political victories. But tonight he’ll need to show some fight without coming across as manufacturing outrage. It’s a fine line to walk and a test that Obama has never really had to pass in past national debates.

Winning once is hard; winning twice is harder: Romney entered the first debate with large majorities assuming that Obama would whup him. Not so in this debate where, according to new Pew Research Center data, 41 percent of people think Obama will win and 37 percent think Romney will emerge victorious. In conversations with lots of sharp GOP operatives and elected officials, there is real concern that Romney benefited from a sort of perfect storm in the first debate (lots of economic talk, Obama checked out, a less-than-assertive moderator, etc.) that he simply won’t be able to recreate this time around. While we tend to think that is a bit too pessimistic — Romney has proven he is an able debater repeatedly during his two presidential bids — it is true that the GOP nominee almost certainly faces a tougher task in this debate than he did in the first one.  Expectations are a tough thing to live up to — stepping over a low bar is a hallmark of The Fix’s professional life — and Romney’s first debate performance set the bar much, much higher, even if he’s not necessarily the clear favorite.