Romney files in New Hampshire, gets Sununu endorsement

CONCORD, N.H. - Mitt Romney made it official on Monday, filing paperwork to become a presidential candidate in New Hampshire, where he has pinned his hopes on a strong victory that will catapult him to the Republican nomination for president.

"It's a big day today," said Romney, who was welcomed by crowd of 200 people at the state Capitol. "We're going to make sure it takes this time!"

When he ran for president in 2008, Romney came in second in New Hampshire after Arizona Sen. John McCain, who went on to secure the Republican nomination. This time around, Romney has focused heavily on winning support from the state's moderate and independent Republicans, and less on the evangelical and socially conservative voters who dominate the Iowa caucus. The states are traditionally the first two to vote in the presidential primaries, a tradition that is likely to continue now that Nevada has backed down from threats to move up its caucus date.

Romney on Monday also secured the endorsement of former Gov. John Sununu, who was President George H.W. Bush's chief of staff. Sununu is still well-regarded in state GOP circles and served as the statewide Republican chairman in the 2010 elections. He accompanied Romney to the Capitol, and praised him as a "solid conservative" and the "strongest candidate to take on President Obama in 2012 and restore fiscal sanity to Washington."

After the rally, Romney addressed the issue of the flat tax, which has been proposed by his leading rivals for the nomination, Texas Gov. Rick Perry and businessman Herman Cain. Speaking with reporters, Romney said he supports a "flatter" tax code but not the more radical flat tax proposal, which would replace the graduated system of income tax rates with a single rate for all taxpayers. Cain has called for a 9-percent flat income tax, while Perry is expected to unveil the particulars of his flat tax proposal on Tuesday.

Romney said, "You've got to look at the details and see, does it help middle-income Americans or not. That's the key. ... And it would be nice if it was a very simple and flat code, but I want to make sure that any tax system that's ultimately put in place is one that reduces that burden on middle-income Americans."

As president, he said he would first try to implement his "59-point" economic plan that does not include a flat tax, and would consider proposals to flatten the tax code later.