DES MOINES, Iowa

•

A squeaker of an Iowa victory behind him, a smiling Mitt Romney jetted to New Hampshire insisting that his staying power sets him apart from caucus runners-up Rick Santorum and Ron Paul and the rest of the GOP presidential field. Michele Bachmann underscored his point by quitting the race, and Rick Perry wavered.

Romney added to his already formidable national network Wednesday with the endorsement of Sen. John McCain. McCain twice won the New Hampshire primary and was the GOP presidential nominee in 2008.

In a sign of the acrimony ahead, Santorum said McCain’s nod was to be expected and took a jab: "John is a more moderate member of the Republican team, and I think he fits in with Mitt’s view of the world."

Jon Huntsman, touring a Pittsfield, N.H., company that makes firefighting suits, dismissed front-runner Romney’s latest catch. Huntsman told reporters that "nobody cares" about McCain’s endorsement of Romney. Huntsman backed McCain’s 2008 presidential bid and campaigned for him in New Hampshire in 2007.

"I have great regard for Sen. McCain. I love the man. But it’s another example of the establishment piling on. And it seems the more the establishment piles on — [Bob] Dole, McCain, all the rest — nobody cares," Huntsman said. Huntsman, a former governor of Utah, has been hoping to follow in the footsteps of McCain, who won the 2000 and 2008 New Hampshire primaries after skipping Iowa’s contest. He calls himself the underdog, and insists New Hampshire voters love underdogs.

The withdrawal of Bachmann, who called herself the true conservative of the bunch, left her supporters up for grabs as the pace of the campaign quickens. That could boost Santorum, whose appeal to Christian conservatives in recent weeks lifted him from the dregs of the opinion polls to become Romney’s top challenger and the conservative of the moment. "Game on," Santorum declared.

Romney was named winner in the wee hours Wednesday — besting Santorum by just eight votes — bringing down the curtain on an improbable first act in the campaign to pick a candidate to challenge President Barack Obama in the fall.