FAIRFAX, Virginia (CNN) -- Sen. John McCain and vice presidential running mate Gov. Sarah Palin campaigned in northern Virginia for the first time on Wednesday, drawing a crowd of more than 20,000 people to a park in the sturdily Democratic county of Fairfax.
"My friends, the commonwealth is Virginia is a battleground state," McCain told the audience, his largest of the campaign so far. "We must win it and we will win it with your support."
McCain's choice to stump in Fairfax County, a populous Washington suburb that went Democratic in the last two presidential elections, might seem unusual for a Republican.
The county is ground zero for a string of recent statewide Democratic victories that have given Obama's campaign hope that it can nab Virginia's 13 electoral votes, which have not gone to a Democrat since 1964.
Sen. Jim Webb, D-Virginia, trounced former Republican Sen. George Allen in the county in 2006 during a hotly contested race for the U.S. Senate, and Tim Kaine racked up healthy margins in Fairfax in the 2005 governor's race.
Despite those recent trends, McCain's campaign believes by campaigning in Obama's backyard, it can blunt the Democrat's performance in a region of the state where he needs to run well in order to win.
"One in seven voters in Virginia lives in Fairfax County," said Trey Walker, mid-Atlantic campaign manager for the McCain campaign. "Clearly Fairfax is a top priority, and northern Virginia is a perfect fit for John McCain and Sarah Palin."
Obama's campaign disputes that claim.
"Today's trip to Virginia, a state his supporters once characterized as an easy win, is an admission that the McCain campaign is concerned that Virginians aren't buying change from a guy who's been in Washington for 26 years and votes with president Bush 90 percent of the time," said Kevin Griffis, an Obama spokesman.
But new CNN/Time Magazine/Opinion Research Corporation polls out Wednesday afternoon in Michigan, Missouri, New Hampshire and Virginia suggest the race between Sens. Obama and McCain is statistically tied.
The poll has McCain leading by four points, 50 percent to 46 percent, in Virginia. President Bush kept the state in the Republican column four years ago.
Virginia hasn't voted for a Democratic presidential candidate since Lyndon Johnson took the state 44 years ago. But Obama is working hard to try and turn the red state blue. He's made numerous campaign stops there, including events Tuesday and Wednesday.
While the overall political climate appears to benefit the Democrats in 2008, thanks to an unpopular president, an unpopular war in Iraq, and an ailing economy, the race for the White House remains tight, both in national polls and state polls.
"The geographic patterns in Virginia make the state look pretty much the same as 2004, with one exception. In the area around Norfolk, Hampton Roads and Virginia Beach -- a region John Kerry lost by four points -- Obama appears to have a 13-point advantage," said CNN polling director Keating Holland.
"That's surprising for an area with several naval bases and the headquarters of Pat Robertson's organization. Obama's getting about the same support in northern Virginia that Kerry did four years ago."
"But that wasn't enough to turn the state blue in 2004, and it's not enough in 2008. Obama needs to do better in Northern Virginia if he hopes to carry the state."
The CNN/Time Magazine/Opinion Research Corporation polls were conducted by telephone Sunday through Tuesday, with 966 registered voters in Michigan, 940 registered voters in Missouri, 899 registered voters in New Hampshire, and 920 registered voters in Virginia.
The survey's sampling error is plus or minus three percentage points in Michigan, Missouri and New Hampshire and 3.5 percentage points in New Hampshire.
Since becoming the de facto Democratic nominee in June, Obama has made nearly a dozen campaign stops in every corner of the state and his campaign has been registering new voters at a breakneck pace. In August, 49,000 new voters signed up in Virginia, 40 percent of whom are under the age of 25.
Meanwhile, McCain's rally in Virginia on Wednesday was his first his first campaign stop of the general election in the state.
But Walker and other Republicans maintain that McCain's maverick image and his military resume give him uncommon appeal in an election year in which the Republican brand is dented. Watch more of McCain and Obama on the campaign trail »
"It's clearly a tough year for the party," said Virginia Rep. Tom Davis, on a conference call organized by the Republican National Committee in July. Still, Davis, a strong McCain supporter, predicted "extraordinary crossover support" for McCain in a year that President Bush's poll numbers "are in the trash can."
Brian Kirwin, a conservative blogger from Virginia Beach, said neither candidate can expect to win the state by campaigning in northern Virginia alone, but predicted that McCain will fare better there than other Republicans.
"If it were Mitt Romney or Tom Tancredo or somebody else, I would say forget about going to northern Virginia," he said. "But John McCain is a different kind of Republican."
The addition of Palin to the Republican ticket is likely to round out Republican support for McCain in Virginia, considering that he lost evangelical and born-again Christians to Mike Huckabee by a factor of two-to-one in the state's primary in February. Polls indicate Palin, who is firmly against abortion rights, has energized the Republican base nationwide.
But in northern Virginia counties like Fairfax, which have leaned Democratic in recent elections, observers say Palin will help McCain boost his appeal among women. Watch more on Palin's effect on the campaign »
"McCain is coming to Fairfax with Sarah Palin to challenge the Democrats on their own turf," said Robert Holsworth, a political science professor at Virginia Commonwealth University. "They want to show suburban appeal, with soccer moms instead of hockey moms, if they can make the sport translate."
CNN's Ed Hornick and Paul Steinhauser contributed to this report.