Long primary battle could help Romney build support A drawn-out fight for the Republican nomination could work to frontrunner Mitt Romney's advantage if he uses it to develop his campaign structure in swing states key to beating President Barack Obama in November. That's what happened in 2008, when Obama built a formidable organization that registered hundreds of thousands of new voters and signed up an army of volunteers during his own long primary battle with Hillary Clinton. With the United States even more deeply divided than it was four years ago as it crawls out of the worst economic downturn in decades, the ability to mobilize supporters could make or break what is expected to be a tight race. "Efforts that produce even small increments in turnout are critical to the outcome," said Michael Traugott, a politics professor at the University of Michigan. Lingering doubts about the former governor of liberal Massachusetts has kept the race in flux as many Republicans search for a candidate with stronger conservative credentials, but who still has a chance of winning over independents and beating Obama. Rival Newt Gingrich has cited Romney's failure to mobilize the base as he vows to fight all the way to the party's August nominating convention despite big wins by his opponent in Florida and last week in Nevada. If you go look at Florida, every county I carried in Florida had an increased turnout (from 2008.) Every county Romney carried in Florida had a decreased turnout," Gingrich said. Now that should sober every Republican in the country. Turnout in Nevada on Saturday -- where Romney won 50 percent of the vote -- was also down, with less than 33,000 people attending caucuses compared with more than 44,000 in 2008. Things will likely change in November, when conservatives who have rallied around calls to make Obama a one-term president have a chance to vote him out of office, said Larry Jacobs, a politics professor at the University of Minnesota. "I don't think you're going to need Newt Gingrich to turn out those people," he told AFP. They're so antagonized by the Obama presidency that they're guaranteed to turn out. Winning over independents and mobilizing less riled-up supporters still requires strong, local organizations able to knock on doors, make phone calls and even drive supporters to the polls. "We have not seen that on the Republican side," an Obama campaign official told AFP. They've gone to all these states and spent a ton of money bashing the president and each other on the air, they have not gone building organization. A great example is the battleground state of New Hampshire, which is closely watched because it also holds the nation's second nominating event, he said. The Obama campaign has seven offices set up in the state, while none of the Republican candidates has more than one. "We had more offices than all their campaigns combined," the campaign official said. We had more staff than all their campaigns combined. We had been banging on doors for months. With the backing of much of the Republican establishment, Romney's well-funded campaign has by far the most sophisticated organization among the remaining contenders. But it's not clear if he has the grassroots volunteer support needed to put those staffers to good use. Just four cars were parked outside his Minnesota campaign office two days before the key battleground state holds its non-binding caucus -- and only one sported a Romney bumper sticker. A poll released Sunday showed Romney in a statistical tie here with Christian conservative Rick Santorum, who is also polling well in Colorado and said he hopes to "reset" the race by putting an end to Romney's win streak. Romney has no plans to campaign in Minnesota -- which he carried in 2008 with 41 percent of the vote -- and is instead concentrating his efforts on Colorado, another swing state that also votes Tuesday. The fact that Romney has a campaign office at all is a sign that he is more deeply engaged in this Midwestern state than usual, said Heather Rubash, press secretary for the Minnesota Republican party. "In past years the race has pretty much been decided by the time it gets to Minnesota," she told AFP. The Romney campaign declined requests for comment.