Veteran electoral number cruncher Michael Barone applies his expertise to former Massachusetts Gov. Mitt Romney’s strategy for winning the Republican presidential nomination in 2012.

There are four contests in January — the Iowa caucuses, and then the primaries in New Hampshire, South Carolina, and Florida. Romney currently trails Newt Gingrich in polls in three of the four. Only in the Granite State does he cling to the lead he has held in every poll there since April 2010.

If New Hampshire follows the pattern of past primaries, Romney should be headed for a win. In 2008, he only narrowly lost the state, 37 percent to 32 percent, to John McCain. He’s been running ahead of that 32 percent in almost all polls this cycle.

He has been building an organization replete with field directors and voter-identification efforts since last May. An absentee-ballot drive is getting underway.

McBride is confident that this organizational effort will deliver. “At the end of the day, the ground game is going to matter.”

Romney has the support of seven of the ten county sheriffs, dozens of state legislators, and legions of Republican activists. Romney signs vastly outnumber those of other candidates on lawns and along highways. …

… Under the old rules, then, Romney seems to have constructed an impregnable firewall in New Hampshire, able to withstand the surge — McBride calls it a “bubble” — for Newt Gingrich that has been sweeping much of the country.

But do the old rules still apply? Sam Pimm, hired a week ago to manage Gingrich’s voter-identification and get-out-the-vote efforts in the state, is not so sure. He helped train candidates that enabled New Hampshire Republicans to gain 122 seats in the 400-member state House in 2010.