Forget the candidates. The outcome of Virginia's race for governor in November may depend primarily on one overriding factor: President Obama's approval rating.
The gubernatorial race between Republican Bob McDonnell and Democrat Creigh Deeds may become a referendum on Obama, as voters look less at the candidates in their state and more at the man in the White House.
Last November, Obama became the first Democratic presidential candidate to win Virginia in 40 years. But in his first six months in office, the president's poll numbers have dropped considerably among independents, who say they are disillusioned by his economic promises and angered by a health care reform bill they say defines him as a big-government spender.
"He's become a double-edged sword in Virginia," said Larry Sabato, director of the Center for Politics at the University of Virginia. "The overall impression is that he's trying to do too much too quickly, and he's becoming identified with big spending and big government.
"That doesn't sell well in Virginia," he said.
Sabato and other political analysts say the Virginia gubernatorial election will be used as a measure of the president and the Democratic Congress.
A Public Policy Polling survey released Aug. 5 shows Obama with a 42 percent approval rating among likely voters in Virginia, while 51 percent disapprove of his performance. The poll shows support among independents dwindling, with 54 percent to 34 percent against him.
But the poll also reflects a disinterest in the gubernatorial race when compared to last year's presidential election.
"Disproportionately, the Obama voters aren't showing up. Off-year elections are used as a message sending to the White House," said Sabato, referring to Republicans unhappy over the president's agenda so far.
Virginia, the only state that limits its governor to a single term at a time, has elected the candidate from the opposite party of the president every four years since 1977.
The same poll found that 53 percent of likely Virginia voters favor the conservative Republican McDonnell, the state's former attorney general, while 47 percent prefer Deeds, a moderate state senator from rural Virginia, who came from behind to win the Democratic primary in June.
Obama is campaigning for Deeds along with Gov. Tim Kaine Thursday night at the McLean Hilton in Northern Virginia -- the president's first campaign rally aimed at boosting Deeds' poll ratings and convincing a base of suburban Washington Democrats to vote for him.
Deeds Communications Director Mike Gehrke told FOXNews.com that he's confident the same voters who brought Obama to victory in November will turn out in sizable numbers for Deeds.
"We can't control Obama's poll numbers -- what we can control is getting our message out," he said. "Those voters who turned out in 2008 are an important part of what we have to do to win."
Gehrke said the Democrats have made considerable gains in fundraising, outracing the Republicans 2-to-1 in the last fundraising period.
The White House is also appealing to the nation's first elected black governor, Virginia's L. Douglas Wilder, to back Deeds. Wilder and Deeds are expected to meet this week.
A strong turnout by black voters, who make up about one-fifth of the Virginia electorate, is critical for Democrats running statewide. Obama earned 92 percent of the black vote in 2008, which pushed the Democratic presidential candidate to victory in the state, the first time in 44 years a Democrat won the Electoral College there.
In 2005, Wilder refused to endorse Deeds against McDonnell in the race for attorney general, and Deeds lost after a six-week recount by 360 votes out of nearly 2 million cast, the closest statewide race ever in Virginia.
Deeds also hasn't won the endorsement of Sheila Johnson, a Democratic mega-donor and billionaire co-founder of the Black Entertainment Television network. She said a few weeks ago that she thought McDonnell would be better for business in the state.
The Virginia governor's race is one of just two statewide elections this year -- the other is for governor of New Jersey, which the GOP needs in the win column as it seeks to revive itself and be well-positioned for the midterm elections in 2010.
Republicans selected McDonnell on Wednesday to deliver the GOP's rebuttal to Obama's weekly radio address -- giving him a national platform to take aim at Obama's health care reform efforts and promises to revive the economy.
The Associated Press contributed to this report.
Cristina Corbin is a Fox News reporter based in New York. Follow her on Twitter @CristinaCorbin.