WASHINGTON _ As he moves unceasingly toward the Republican presidential nomination, Mitt Romney has cast himself as the only GOP candidate with an organization hefty enough to take on President Barack Obama's campaign juggernaut.

"The other guys are nice folks, but they haven't organized a campaign with a staff, the organization, the fundraising capacity to actually beat Barack Obama," Romney said this month on Fox News. "I have."

But an examination of how the two campaigns have spent their money in the last year starkly illustrates the huge advantage Obama will have in mounting a ground operation to identify voters and get them to the polls in November.

Spared a primary opponent, the President's reelection campaign by the end of February had pumped nearly $79 million into laying the groundwork for the general election, deploying staff to far-flung corners of the country such as Laramie, Wyo., and Lebanon, N.H., as part of an ambitious, tech-savvy field effort.

Romney, mired for months in a contentious primary, has not yet devoted substantial resources to a national field program. Of the $68 million spent so far by his campaign, $25.4 million went to fundraising and media ads in primary states, elements that -- while key to his front-runner standing -- may not translate into lasting gains.

He has spent only $5 million on staff, compared with the $20 million Obama has doled out for his campaign workers. For its reach, Romney's campaign plans to lean on the Republican Party, which has yet to set up shop in states long inhabited by Obama operatives.

The spending data and interviews with campaign officials suggest that a Romney-Obama race would be a clash between distinct political philosophies, one that would test the power of an aerial bombardment through television ads against an in-person voter mobilization months in the making.

Both campaigns will employ commercials and ground organizers to make their cases, of course. But media use is the specialty of top Romney campaign officials Matt Rhoades, Eric Fehrnstrom, Stuart Stevens and Russ Schriefer, who have backgrounds in communications and ad production. And Romney is poised to benefit from intense air cover provided by Restore Our Future, a "super PAC" that has already spent $37 million, largely on TV ads attacking his GOP rivals.

Romney campaign strategists acknowledge they currently have a small field operation, by design. Instead of hiring get-out-the-vote organizers around the country, a lean team has leapfrogged in and out of the various primary states. That has kept costs down, but it also means Romney has a smaller national footprint than Obama.

Campaign political director Rich Beeson said he had kept some staff in states that would be key for the general election. But he said the bulk of the voter registration and mobilization program for the fall would be handled by the Republican National Committee.

"It has the infrastructure in place," he said. "We're taking care of business in the primary, setting up infrastructure in states that make sense in a general. But at the end of the day, I'm not losing sleep over having a general election field operation. I know that's being taken care of."

That's a very different philosophy from that of Obama and his top political aides, David Plouffe and David Axelrod. In 2008, Obama's operation wrested the Democratic nomination on the strength of an unprecedented field operation that -- in tandem with massive fundraising -- lifted the former community organizer over the establishment candidate, Hillary Rodham Clinton.

The campaign appears poised to be even more aggressive this year. Volunteers are registering new voters in an effort to expand the pool of supporters. They are knocking on doors to identify likely voters -- an activity that usually occurs in the summer or fall. And the reelection effort has begun blanketing battleground states with field offices, including 18 in Florida, 13 in Pennsylvania and eight in Iowa. In the process, Obama's apparatus has locked up local Democratic operatives across the country much earlier than expected.

"It's made it tougher to find good staff for local campaigns," said Jim Ross, a San Francisco-based Democratic strategist who runs campaigns in California, Oregon and Nevada.

That traditional field work is being buttressed by a massive technological investment aimed at expanding the campaign's voter database, which in turn fuels the organizing efforts. Nearly a fifth of the campaign's spending so far -- $15.1 million -- went to online advertising, technology consulting and Web hosting. The campaign recently opened a field office in San Francisco for volunteers who want to contribute their high-tech skills to Web development and other projects.

Obama's reelection effort also will draw on the resources of the Democratic National Committee, for which he's helped raise $138 million in the last year.

"You won't be able to compete with the Obama ground game," admitted Doug Gross, a veteran GOP activist and Romney's 2008 Iowa chairman. But he and other Republicans, including Beeson, argue that the President needs a more substantial field effort to offset his drop-off in popularity since 2008.

"For the Republicans, what's going to drive turnout is not going to be Mitt Romney -- it's Barack Obama," Gross said.

Still, there's no question that field efforts can make the critical difference in tight races. Many political strategists attribute President George W. Bush's 2004 reelection to a sophisticated get-out-the-vote operation designed by Karl Rove. Romney, several GOP strategists said, has opted for a different approach.

"A strong field organization does not appear to have been a priority for the campaign," said one operative in Ohio who did not want to be identified while critiquing the campaign. "I think that is something they are hoping for the party or other organizations to provide."

Romney officials disputed the idea that the campaign has not put a premium on reaching out to voters, pointing to a sophisticated micro-targeting operation it ran in New Hampshire and early voting and absentee ballot programs that gave him an edge in states such as Florida and Michigan.

"Anytime there's been an opportunity to put votes in the bank before Election Day, we've done that," Beeson said. "You don't just do that with media. There has to be an operation on the ground that's turning out votes."

If and when Romney secures the nomination, the campaign's existing field program would fold into Republican National Committee efforts already underway. That's a marked difference from 2008, when officials said they deferred to the John McCain campaign on hiring staff, delaying the launch of state field offices until June.

This year, the RNC plans to have 50 percent more field staff than it did in 2008, said political director Rick Wiley. The first offices opened this month in Florida, North Carolina and Virginia. Next month, the party will set up shop in six more states, including Ohio -- a place where Obama already has 12 offices.

Wiley acknowledged that the RNC can't fully unleash its entire 2012 operation, which will cost hundreds of millions of dollars, until there is a GOP presidential nominee who can help raise money for the party's efforts.

"When we get that nominee, boom," he said.

(Los Angeles Times staff writers Maloy Moore and Maeve Reston contributed to this report.)