With Mitt Romney pulling away in the polls, his opponents are looking to knock him off his game during a pair of debates which could represent their best shot at changing up the race before the New Hampshire primary.

A win by Romney in the Granite State would appear a foregone conclusion, considering he's enjoyed a double-digit lead in the state in virtually every poll since polling began. But while some analysts are calling the primary a battle among his opponents for second place, the field of competitors is keen to at least deprive Romney of a crushing victory Tuesday which could help bolster an image of inevitability going into South Carolina and other contests.

Newt Gingrich on Friday night held an event where he urged primary voters not to "mass up" on election day, a dig at Romney's days as Massachusetts governor.

"We're drawing a sharp contrast. I am a Reagan conservative. He is a Massachusetts moderate," Gingrich told Fox News on Saturday. "There are really big gaps between where the two of us stand."

Previewing the strategy ahead, Gingrich accused Romney of backing tax hikes as well as allowing the funding of abortions in his state health care plan. Gingrich's campaign is planning to release an ad focused on Romney's abortion record, though the former House speaker said Saturday he will avoid "negative" ads.

The candidates will have a chance to articulate their concerns with Romney at a debate Saturday night, followed by another Sunday morning. There are fewer than 12 hours between the ABC News/WMUR debate Saturday and the NBC News/Facebook debate on Sunday's "Meet the Press."

Gingrich said he plans to draw contrasts with his opponents, but said of the debates, "I'm not going to be nasty or mean-spirited."

Ahead of the grueling rhetorical task ahead, Gingrich was holding a town hall in New Hampshire Saturday, as were Romney and former Utah Gov. Jon Huntsman, who is banking on New Hampshire to keep his struggling campaign afloat. Rick Santorum, the former Pennsylvania senator who finished a few votes behind Romney in the Iowa caucuses, had a string of events scheduled for Saturday as he pursues the same kind of retail politics in New Hampshire that helped propel him from the back of the pack to the front in Iowa.

Both Santorum and Romney have enjoyed a surge in the polls coming out of the caucuses. But Romney appears to be pulling away for the moment. In New Hampshire, a new Rasmussen Reports poll showed him leading by 24 points. The candidate who was seemingly unable to break the 25-point threshold in Iowa was clocking in at 42 percent in New Hampshire, followed by Ron Paul with 18 percent and Santorum with 13 percent.

With Gingrich's numbers going down, Romney has also returned to the lead in national polls, and in South Carolina polls. Several surveys released Friday showed Romney seizing the lead from Gingrich in the Palmetto State, with Santorum and Gingrich jockeying for second position.

South Carolina historically has been the most critical early GOP primary contest, and Romney's opponents are determined to keep him from going three-for-three. They routinely raise questions about whether he has the conservative core that primary voters are looking for.

"The only way Republicans lose is if we screw this up and nominate another moderate who has taken multiple positions on every major issue of our time," Santorum wrote supporters in a fundraising appeal.

Santorum is set to leave Sunday for South Carolina for a half-day of campaigning. Romney has events planned in New Hampshire through primary day on Tuesday.

Gingrich has been talking of merely holding Romney's winning total under 50 percent in New Hampshire while Paul, who arrived in the state on Friday, has focused his criticism on Santorum.

"He brags about being for a balanced budget amendment but never did anything about it," Paul said of Santorum's time in the Senate. "He voted four or five times to raise the debt ceiling. He voted to double the size of the Department of Education."

The Associated Press contributed to this report.