A lot will be on the line tonight for Rick Perry, Mitt Romney, Herman Cain and Jon Huntsman Jr. when they and four other Republican presidential candidates take the stage at Dartmouth College in New Hampshire for the Bloomberg/Washington Post debate that will focus on the U.S. economy.

Perry, after giving subpar performances during the last two GOP debates and subsequently sliding in the polls, is in a now-or-never position, Politico reports.

"If Perry stumbles again, coming off as inarticulate or defensive, the damage to his campaign could prove terminal. One bad debate turn for a new candidate may be excusable, but two is troubling. To turn in three or even four weak showings would be more than sufficient to send donors and voters alike scurrying away for good."

Debate moderator Charlie Rose said Tuesday on the MSNBC "Morning Joe" show that he intends to pepper candidates with questions about the Occupy Wall Street protests. Republican frontrunner Romney, buoyed by the announcement Tuesday he will receive the endorsement of New Jersey Gov. Chris Christie, will almost certainly face some of those queries after denouncing the movement Monday.

"We have a very capable financial services sector that makes loans and allows business to start and thrive," Romney said during a question-and-answer session. "Are there bad actors on Wall Street? Absolutely. And are there bad actors on Main Street? Absolutely. All the streets are connected — Wall Street's connected to Main Street. And so finding a scapegoat, finding someone to blame, in my opinion isn't the right way to go."

By pulling down 16-18 percent of the votes in recent GOP presidential polling, Cain has surged ahead of Perry. Also, a new national Gallup poll pegs Cain nipping at Romney's heels, with the former Massachusetts governor clinging to a 20-18 lead. Now Cain will try to carry that momentum into Tuesday's debate.

"If Cain's top-tier status is without question, what he will do with it in tonight's debate is very much up in the air," the Washington Post's blog "The Fix" mused Tuesday. "Cain can be a dynamic presence with his rhetorical gifts and ability to turn a phrase. But he can also fall too much in love with his knack for candor. Remember that Cain asserted he wouldn't let a Muslim serve in his presidential cabinet during the last debate in New Hampshire. He later recanted."

For better or worse, Huntsman is digging in his heels by making New Hampshire's first-in-the-nation primary the defining moment of his campaign. Although Huntsman received only 4 percent of the votes in a new Harvard/St. Anselm poll of Granite State voters, New York Times elections analyst extraordinaire Nate Silver thinks the former Utah governor could still come up big in New Hampshire.

"Huntsman's polling in New Hampshire — where he averages about 7 percent of the vote — has been a little bit livelier than in other states," Silver wrote Monday. "Even if he's very unlikely to win the nomination, perhaps Mr. Huntsman could at least create some drama in New Hampshire, where his moderation might play comparatively well, as John McCain's did in 2000."

Today's debate will begin at 6 p.m. MST and can be viewed online at PostPolitics.com. The Twitter hashtag associated with the debate is #econdebate.

EMAIL: jaskar@desnews.com