Now it’s official: Mitt Romney is the front-runner to win the New Hampshire primary. But New Hampshire doesn’t like one candidate to lead wire-to-wire without being severely tested. Just ask John McCain, Bob Dole and both George Bushes.

Someone is going to win the primary within the primary, the one in which the rest of the field competes to become the principal alternative to Romney. Whether this alternative will come from the mainstream of the Republican Party, like Romney was to McCain in 2008; or whether it will be an insurgent outsider, like Pat Buchanan was to Bob Dole in 1996, is an open question. The mood and composition of the electorate is never the same from one primary to the next. John McCain version 2008 would have a hard time being nominated by the 2012 Republican primary electorate.

Last year’s Republican U.S. Senate primary could serve as a template for next winter’s presidential primary. In that race, Kelly Ayotte was the front-runner all along while her three major opponents took turns competing to be viewed as the main alternative to Ayotte. In the end, Ovide Lamontagne emerged as the alternative with the best chance to win, and support for Bill Binnie and Jim Bender migrated to Lamontagne in the closing week of the campaign. Something similar could happen in the presidential race — including a huge surge to one candidate all in the final days.

So take heart, Tim Pawlenty and Rick Santorum. This is the part of the campaign where you operate on faith that 12 months of daily slog, during which you’ve done everything you’re supposed to do, yet have seen little tangible evidence that you’ve made much progress, will one day pay off. Every candidate who’s ever won has been where you are. Keep pluggin’.

If it’s a mainstream alternative who emerges, Gov. Jon Huntsman may have the best shot. While most of the other candidates chase the same 20-25 percent of the electorate who self-identify with the Tea Party, Huntsman is making a direct appeal to mainstream conservatives and the Republican-leaning independents who will probably outnumber Tea Partiers on primary day.

At a house party in Durham last week, Huntsman made a good first impression, though his remarks were short on substance and he took no questions from the audience. A small number of Republicans think you can’t be a good conservative unless you’re grumpy all the time. Huntsman won’t be their guy, but he’s going to get market share as he becomes better known.

If it’s a Buchanan-style insurgent alternative, Rep. Michele Bachmann could emerge, especially if she does well in Iowa. At a house party in Dover earlier this week, Bachmann was high energy and charismatic. She connected with very conservative members of the audience, deftly pressing their hot buttons without sounding extreme. Bachmann’s a good communicator, and she will stand out on a stage when many others blend together.

Yesterday, Rudy Giuliani started his third visit to New Hampshire this year, headlining a Dover fundraiser for the state Republican Party. It’s good of him to do that; few Republicans have traveled as often and done as many party-building events as Giuliani has over the past two decades. His name recognition gives him an advantage in early polling, just as it did four years ago. With several major Republicans opting out, it’s understandable that Giuliani would take a fresh look at the race.

That said, there’s no evidence that Giuliani has enough support to run. This week I contacted 15 of the 37 Granite Staters listed as Giuliani delegates or alternates from 2008. Only three reported having had any contact from the Giuliani organization since the last primary. The rest had not received so much as a courtesy call, let alone an invitation to reconnect. Just three said they would support Giuliani again, should he run.

One 2008 Giuliani delegate, Stella Scamman, co-hosted Romney’s big announcement in Stratham yesterday. Another Guiliani delegate, former state Rep. Jim Devine, was so committed last time that he had a vanity license plate reading, “RUDY08.”

“I’ve moved on,” Devine told me. His new vanity plate? “PALIN12.”

Fergus Cullen, a freelance columnist, is a former chairman of the New Hampshire Republican Party. He can be reached at fergus@ferguscullen.com.