Sens. John McCain and Barack Obama are both counting on Iowa to help deliver them to the White House.

Both campaigns have invested heavily in Iowa, and the top operatives for each side agree the outcome is still very much up in the air. While the state seems to be trending Democratic, recent polls show McCain making up ground as Election Day draws near.

“If we didn’t think Iowa was important, if it wasn’t a key battleground for us, we wouldn’t be putting a huge investment in TV, radio and people on the ground,” said Gentry Collins, Midwest regional director for the McCain campaign. “Campaigns have a finite amount of resources, both in terms of finances and in terms of time. I think you’ll find that major national campaigns don’t waste a lot of time on states they don’t believe are key to their electoral fortunes. And in Iowa, we’re making a very large investment.”

Obama’s lead in the state is shrinking, from 9 percentage points last month to 5 this month, according to a recent Rasmussen poll. A Pollster.com survey showed the Illinois senator with a 48-42 lead.

But the number of registered Democrats has increased 16 percent since mid-2004, when President Bush carried Iowa by only 10,000 votes. Trailing Republicans by roughly 8,000 in the summer before the 2004 election, registered Democrats now outnumber them by more than 90,000, according to statistics from the Iowa secretary of state, which also show that Democrats are within reach of overtaking the number of registered independents.

There is also a growing disparity in the number of people on the ground for both campaigns. Obama has 30 field offices located around the state, in urban settings like Des Moines and Cedar Rapids and in more rural places like Independence and Fairfield. A recent Iowa Independent story found a tight race in the fastest growing area of the state, Dallas County, west of Des Moines.

“One of the philosophies we’ve always had in our campaign is that we need to include everybody, not just larger urban areas where there will be big turnout,” said Jackie Norris, state director for Obama’s Iowa campaign. “This is going to be a campaign that’s won with all 99 counties participating. That’s why you see offices opening up in places like Ottumwa or Muscatine and other less urban areas around the state.”

The McCain campaign has only seven field offices in Iowa , each located in an urban center. But Dave Roederer, McCain’s state chairman, said the campaign benefits from being the headquarters for the Midwest regional headquarters.

Located in Urbandale, the regional office oversees operations in Iowa, Missouri and Illinois. Roederer said this allows decisions made in Washington, D.C., to get to the ground more quickly and for input to make its way from the ground to Washington more efficiently.

“I think this is a great organization, and I think it makes the entire campaign more effective,” he said.

The number of feet on the ground will be boosted by the Republican National Committee and the Republican Party of Iowa, Collins said, but so far that hasn’t been the case. The Iowa Independent reported in July that documents filed with the Federal Election Commission showed the Republican Party of Iowa had only seven salaried employees on staff, compared to 28 for the state Democrats. That difference has ballooned since then, with documents filed in August showing Democrats with more than 100 paid staff in the field while the GOP still has only seven.

Documents filed with the Iowa Ethics and Campaign Disclosure Board shows the RPI has no paid staff focusing exclusively on state races while the state Democratic Party has 34.

Neither campaign has been willing to share the number of staff on their payroll working in Iowa.

State Republican strategists have said previously that the GOP relies more on volunteers at the county levels than on paid staff.

Norris said the Obama campaign is working to ensure Democrats up and down the ticket are successful and to boost turnout in traditionally Republican precincts. After the Democratic convention is complete and delegates return home, Norris said field organizers for the Obama campaign around the state will hit the streets with literature for Democratic candidates at all levels, from national offices to state legislative races.

“They will be talking about the ticket and the need to get all of our candidates elected,” she said.

Roederer said he’s still confident in McCain’s chances in Iowa, as he believes experience is the one issue that will carry the day.

“With experience comes a comfort level of knowing that the next president is going to be inheriting a difficult world,” he said. “John McCain has been tested. He has laid out very specific plans about all the major issues. That is the kind of thing that will be on people’s minds when they go to vote.”

During his visit to Ames this afternoon to stump for Sen. John McCain, Pawlenty said voting for Obama to be the next president is too risky, comparing it to bungee jumping. Obama Spokeswoman Jenni Lee said the statement is another example of McCain taking the low road.

“With fewer than 100 days before the election, Sen. McCain and his campaign continue to take the low road and resort to negative, desperate, and false attacks,” Lee said in a statement. “While Sen. McCain’s energy plan hands out nearly $4 billion in tax breaks to oil companies and invests almost nothing in new energy sources, Sen. Obama will provide tax rebates to families and create a renewable energy economy in America that will free us from our dependence on foreign oil.”

McCain is leading in spending, with $946,000 spent on advertising in Iowa compared with $700,000 by Obama’s campaign. Nationwide, since the end of the primary season (June 3) through July 26, the two presidential candidates have aired ads more than 100,000 times nationally on broadcast television, compared to 77,000 times during the same period in 2004. The McCain campaign has spent just over $21 million on television advertising since June 3, while Obama has spent over $27 million.

McCain did take advantage of the prolonged Democratic primary, the report said, airing 5,374 ads and spending $2.2 million prior to June 3. These ads were aired in Iowa, Michigan, Ohio, Pennsylvania and West Virginia and are not included in the totals in the report issued today.

“Obama’s fund-raising totals allow his campaign to purchase more ads,” Ken Goldstein, director of the Wisconsin Advertising Project, said in a statement, “but, to this point, we have yet to see that advantage translate to a massive advantage in paid media.”

While Obama is spreading out his ads across many states, McCain is focusing on four key states – Michigan, Ohio, Pennsylvania, and Wisconsin, according to the project’s analysis of data from TNS Media Intelligence/CMAG, a non-partisan organization that provides data and analysis for political, public affairs and issue advocacy advertising.

There are five states where Obama is advertising and McCain is not. Those include Alaska, Georgia, Indiana, Montana and North Carolina. Of those, 2004 Democratic presidential nominee John Kerry only advertised in North Carolina.

“It is certainly worth noting that Obama is up in these red states and has the airways all to himself,” Goldstein said.

Although Obama has spent $6 million more than McCain on television advertising nationwide, if the spending by the Republican National Committee is included,the margin decreases to $2.3 million.

“In general, the campaign advertising appears to be mostly about Obama and less about McCain. Over 90 percent of the ads aired by Obama are positive in nature and do not mention Sen. McCain.In contrast, approximately a third of the McCain campaign’s ads are negative, contrasting the two presidential candidates.”