and Dan Eggen

When President Obama campaigned in Las Vegas on Wednesday, his aides had laid the groundwork by opening 18 field offices around the city. Mitt Romney’s state operation has opened three.

In the critical battleground state, the Nevada Democratic Party has been building staff for two years and now has nearly 200 people organizing volunteers, knocking on doors, registering voters and compiling lists of supporters. Romney’s Nevada campaign is backed up by about 40 workers.

In Ohio, another closely fought swing state, the Democratic state party employs nearly 300 people, more than the Republican National Committee in Washington, and almost four times as many as the Ohio GOP.

That gap in the candidates’ ground efforts is mirrored around the country as the presidential contest heads into its final weeks, with Democratic campaign workers outnumbering Republicans nearly three to one, according to a Washington Post analysis of campaign spending reports.

The numbers reflect a fundamental difference in the way the rival campaigns are deploying resources as they battle to capture the presidency. Obama is spending earlier and investing more in his state campaign infrastructure, putting a bigger emphasis on person-to-person contact with potential voters.

Romney and Republicans are focusing more on advertising and stockpiling funds, anticipating a significant and growing money advantage in the fall. The GOP candidate and his allies — the party and independent groups — have $105 million more sitting in bank accounts than the Democrats. For the period after the conventions, they could easily outspend Democrats two to one, with most of it likely to go to more television ads.

“We’re a little wiser in our spending of dollars than the other side, apparently,” Romney told donors in Texas this week. “I’m not managing their campaign for them, but we’re going to spend our money wisely. We’re going to spend it to win.”

Obama campaign manager Jim Messina countered that the Republicans have “already missed a year of persuasion on the ground.”

“At some point, people are going to look to their friends and neighbors about what decision they’re going to make,” Messina said. “We think that’s going to be a big chunk of how we win this thing.”

The Obama campaign and the Democratic National Committee have transferred $50 million to swing states around the country to open field offices and hire campaign organizers, new spending reports show. That compares to $8 million Romney and the Republican National Committee have sent to state parties.

RNC officials said that staff numbers do not reflect their volunteer support, saying the party has made 12 million personal contacts with voters nationally and is on pace to surpass the voter-contact number of all previous Republican campaigns.

“The Obama campaign is quick to tout how many people they have on payroll, but they don’t seem to be doing anything,” said Rick Wiley, the RNC’s political director. “It is really expensive to put field staff and offices in there. I can only imagine how much money they’re burning through.”

On top of its field offices, the president’s campaign has invested in a more sophisticated Internet strategy than the Republicans’ — creating, for example, a Web site called Dashboard where supporters can create profiles, join neighborhood canvassing teams, send event invitations and watch videos.

The Obama campaign also released a smartphone application that allows any supporter to pull up lists of nearby Democrats, who can then be targeted with appeals to vote.

Democrats say their efforts are paying off. In Nevada, they have registered 17,464 voters since January, compared to 9,747 new voters who identified themselves as Republicans, the secretary of state’s office reports.

Obama’s big presence in the state is the culmination of years of work building support among Latinos and other newly emerging voters, Democrats say. They point to Obama’s victory in 2008 and Senate Majority Leader Harry Reid’s successful reelection in 2010 as proof of the benefits of grass-roots organizing.

“You can’t underestimate the importance of a ground game in a state like Nevada,” said Zac Petkanas, senior communications adviser to the state’s Democratic Party. “We showed what it could do in 2010 against all odds, and before that in 2008.”

This week, Obama urged supporters in Las Vegas to register to vote with help from Democratic staffers or through a special Web site set up by the campaign. “So that means you can grab your friends, grab your neighbors, grab your aunt, grab your uncle, cousins, and you can register,” the president told a crowd.

The RNC also has created a smartphone application for canvassing and a “Social Victory Center” on Facebook, which helps volunteers make phone calls to nearby swing-state voters and record survey responses instantly.

Obama enjoyed a similar advantage in field operations in 2008 against Republican presidential nominee John McCain. But in that election, Democrats had a huge funding advantage in the final months of the campaign after Obama opted out of public financing and the spending cap that accompanies it.

Ed Rogers, a Republican strategist and chairman of the BGR Group, said Obama is attempting to create “synthetic, steroid-driven turnout” because the “romantic enthusiasm” he had four years ago is gone. Rogers said the resources Romney has for advertising will allow him to chip away at Obama’s advantage as an incumbent.

“That’s the Obama plan to win a close one — to have superior turnout mechanisms,” Rogers said. “But doing that without much enthusiasm is hard.”

Obama’s campaign has so far remained even with Romney and his backers on television ad spending. But Republicans, with their larger bank account, are likely to dominate the airwaves in the fall.

The large Republican spending advantage in the fall may not go as far as the numbers suggest, however, because Obama has more money in his campaign bank account, while more of Romney’s money is the Republican party’s account.

That will allow the president’s campaign to pay less for television rates than the RNC or super PACS — federal laws entitle campaigns to the cheapest rates. Also, candidates have complete control of the funds in their campaign coffers, but they can direct just part of the money raised for the party.

Democrats maintain that voters will tune out the messages on television once they reach a certain saturation.

“Past saturation, twice as much does not mean twice as powerful,” said Jim Jordan, a Democratic strategist and former aide to Sen. John Kerry (D-Mass.). “And that’s especially true given Obama’s truly significant advantage in the ground and turnout game.”