Boston Globe Correspondent Callum Borchers reports that two third-party presidential candidates will participate in an expanded version of tonight’s debate between President Obama and Republican nominee Mitt Romney on satellite TV and online.

Green Party candidate Jill Stein and Justice Party candidate Rocky Anderson will respond to the same questions posed to Obama and Romney on Democracy Now!, which will show the Obama-Romney debate, but pause after the major-party candidates’ responses to allow Stein and Anderson to deliver their own remarks.

90 minutes before the debate, Harry Reid goes after Romney on the Dream Act, calling him "out of touch with the nation in which he lives.”

RT @EmilyABC: Romney has arrived on site at the Denver debate.

RT @markknoller: McCurry says total of 140 presidential candidates nationwide - but only 2 are meet Debate Commission eligibility standards.

This is Michael Kranish, Washington Bureau deputy chief. I'll be part of a team of Boston Globe reporters in Denver, Boston and Washington preparing to live-blog, fact-check and analyze tonight's presidential debate.

Amid all the pre-debate analysis, this New Yorker cartoon is a reporter's thought bubble: will tonight be by the script or will it surprise? www.newyorker.com

RT @nytjim: RT @baratunde: Oh wow @JoeBiden will be livetweeting the #debates!!!

CAMPAIGN 2012: Obama motorcade arrives at debate site...

Per the White House pool report, “The pool heard cheers and chants of ‘four more years’ from a good size crowd opposite the hotel.”

RT @dgjackson: Backstage with family playing jenga. p.twimg.com

The president has arrived at the debate hall.

And the Romney campaign is already e-mailing about its “rapid-response” site.

In fairness, the Obama campaign is up and running, too.

For those watching at home, consider this: Tonight is the 20th wedding anniversary for Barack and Michelle Obama.

Greetings, I'm Meg Woolhouse. I cover economic news for The Boston Globe, Boston.com, and BostonGlobe.com. I'll be especially interested to hear -- and parse -- the candidates' views of Mitt Romney's tenure as governor of Massachusetts. Hopefully we'll also learn more about both candidates' job creation and economic recovery plans tonight as well!

Audience told their seats can disappear. "If you break the rules, a button will be pushed, and you’ll be swimming with the fishes."

Hi all, I'm Chelsea Conaboy. I cover health care for the Globe and on the White Coat Notes blog on Boston.com. I'm anxious to see a fuller conversation about the federal health law and its relationship to the state's 2006 law. As Rob said, while the broader national debate has focused a lot on the Affordable Care Act, the candidates have not spent much time on it to date.

Beth Healy here - Globe financial writer helping fact check on Romney's career at Bain and related business matters

Ann Romney walks over to embrace Michelle Obama as they are introduced. Believe it is the first time they have met.

There is a sisterhood for candidate spouses, who endure plenty of angst in long race.

Behind Ann Romney is Scott Romney, the nominee’s older brother.

For a presidential debate veteran, Michelle Obama appears nervous.

ANALYSIS: The stakes for Mitt Romney in tonight’s debate are, as they say in Denver, a mile high. Challengers usually have more at stake in a debate, and they can gain or lose much in a single sentence.

Romney knows this well; his father, George, famously withdrew from his 1968 presidential campaign after saying he had been brainwashed by US generals in Vietnam. Mitt Romney has learned – some would so over-learned – that lesson. When he veers off script, he has had problems. But a debate that seems to be scripted might not be enough for him. So he has spent weeks preparing for off-the-cuff attacks, as contradictory as that may sound. His team wants him to stay on message without seeming to be reading from a script.

Romney is a practiced debater. This will be Romney’s 20th debate in this campaign, with the others coming in the Republican primaries. He has not had a one-on-one debate in a general election since his 2002 gubernatorial race against Shannon O’Brien.

Obama, while perceived by many to be the better debater, has not had nearly as much live practice recently; the president has not been in a debate since 2008, when he faced Republican nominee John McCain. The challenge for both men is clear: they will be trying to show that they understand the concerns of everyday Americans in a difficult economy. Obama and Romney will be standing across from each, lobbing attacks and counter-attacks, but their mission is to try to connect in a personal way to the television viewers they cannot see, and win over the voters who will determine who is inaugurated in January.