WASHINGTON - Republican front-runners New Gingrich and Mitt Romney are in New Hampshire on Monday then return to Iowa later in the week, focusing on voters in the two states that kick off the U.S. presidential nominating process just days after the New Year.

Polls show Gingrich, the former speaker of the House of Representatives, pulling away from former Massachusetts governor Romney, a stunning turnaround after Romney had been coasting at the top of the pack through the early months of the campaign for the Republican nomination to challenge President Barack Obama in the November 2012 election.

The Republican candidates will assemble again this week to debate, on Thursday in Iowa. On Jan. 3, the state holds caucuses to begin the national selection process for delegates committed to one of the candidates at the Republican national convention in late summer. Seven days later, New Hampshire holds the nation's first primary election.

Both contests have historically served as major events in shaping the race moving forward in the drawn out state-by-state primary votes.

Obama's approval rating has sunk to record lows over his handling to the American economic recovery, but the chaotic Republican race has kept much negative attention on the party as a number of candidates have flamed out after briefly moving into the top tier.

Rep. Michele Bachmann shot up in polls then quickly fell back, ceding the role as Romney's more conservative challenger to Texas Gov. Rick Perry. Perry's stumbling debate performances badly damaged his effort, and businessman Herman Cain stepped into the void to briefly pass Romney in some polls. But allegations of sexual harassment and a 13-year extramarital affair forced him out of the race.

Gingrich has showed far more staying power and is now easily outdistancing Romney in national polls. He remains a controversial figure because of his past record as House speaker, a job he left under a cloud of ethics violations, and a personal life that includes three marriages and admitted infidelities to his wives. The latter would normally exclude support from evangelical Christians, a huge and powerful Republican force, but so far his public repentance of past behaviour seems to have satisfied the deeply conservative segment of the party.

Romney faces a huge challenge now that Gingrich has taken the top spot. Both candidates have held positions in the past that are viewed as far too moderate or liberal for Republican primary voters, but Gingrich has apparently been more convincing in his shift to the right. Romney also is hurt with Christian Republican voters who are suspicious of his Mormon faith.

What's more, Romney is heavily encumbered with his record as governor of Democratic-dominated Massachusetts, where he was responsible for an overhaul of the state's health care system, putting in place a program that served as a model for Obama's nationwide revisions. Republicans call the new health care law "Obamacare" and vow to rescind the law that requires all Americans to buy health insurance.

Gingrich, who has converted to Roman Catholicism, also has supported the insurance mandate in the past but has managed to explain himself in a way that appears to have satisfied Republican primary voters.

As in past nominating fights, libertarian Texas Rep. Ron Paul is playing the wild-card role and currently is running third in Iowa. He has found significant support for his calls for a much diminished U.S. federal government and the smaller tax bite that would be necessary to run it.

Former Utah Gov. Jon Huntsman, who served as Obama's first ambassador to China, is dead last in most polls, appearing to have been cast away by likely Republican primary voters as too moderate.

On Wednesday in Iowa, Gingrich, Perry, Bachmann and former Pennsylvania Sen. Rick Santorum will meet with the 2008 Iowa winner, Mike Huckabee. Huckabee served as governor of Arkansas and is an ordained Southern Baptist minister.

Perry and Bachmann hope the Iowa caucuses with reinvigorate their campaigns. Bachmann won the August Republican straw poll in Iowa, the state where she was born, before ceding her spot as the top Romney challenger to Perry, who announced his candidacy in the state just a day later. Both Perry and Bachmann openly talk about their conservative Christian beliefs, something that tends to play well with Iowa Republicans as is testified by Huckabee's success there four years ago.