Mitt Romney secured two important endorsements in New Hampshire over the weekend, bolstering his presidential campaign in response to a surge by Newt Gingrich.

Sen. Kelly Ayotte announced her endorsement on Sunday, followed by U.S. Rep. Charlie Bass on Monday. They join former Gov. John Sununu and former Sen. Judd Gregg in the growing group of New Hampshire politicians supporting Romney. U.S. Rep. Frank Guinta is the only Republican in New Hampshire's federal delegation who has not endorsed Romney.

Bass -- who said in his announcement that Romney has the experience of creating jobs and has the leadership qualities needed to bring the citizens of our nation back together in these challenging times -- is a moderate Republican, so his endorsement is not surprising. Ayotte's endorsement, however, is highly significant because she is socially conservative, and Romney has struggled to win the support of social conservatives.

Critics have accused Romney of flip-flopping on issues like health care, abortion and same-sex marriage. His positions are conservative now, but many voters are suspicious because he held more moderate positions as governor of Massachusetts. Endorsements from prominent conservatives are probably his best hope for winning over those voters, and Ayotte -- whose 2010 campaign was backed by Sarah Palin -- is conservative on every major issue.

Sees Romney As Most Electable Candidate

Ayotte represents a segment of the Republican Party that may not agree with all of Romney's positions but sees him as the most electable candidate.

There's one person in this field who is prepared to lead the United States of America, and that is Mitt Romney, Ayotte said in Nashua, N.H., on Sunday. And most importantly, there is one person who I know will ensure that Barack Obama is a one-term president, and that is Mitt Romney.

Ayotte added that she and her husband would campaign actively for Romney.

Joe and I will be doing everything we can to make sure Mitt Romney is the next president of the United States, she said. We cannot take four more years of this president.

New Hampshire will hold the first primary of the 2012 campaign on Jan. 10, one week after Iowa's first-in-the-nation caucuses. Romney has held double-digit leads in every poll in New Hampshire since April, except for two: a Public Policy Polling survey in early July and a Magellan poll conducted Nov. 15-16, which found him in a statistical tie with former House Speaker Newt Gingrich.

Gingrich has shot up in the polls in the past week or so, benefiting from the losses of former front-runner Herman Cain, but it remains to be seen whether he can remain competitive in a state where Romney has the strongest campaign infrastructure and a near-sweep of prominent endorsements.