Sen. Barack Obama has gained ground in Virginia and is virtually tied with Sen. John McCain in an early indication of how competitive the state is shaping up to be this fall.

But the benefit of picking a Democratic running mate from Virginia is questionable, a Rasmussen Reports survey suggests.

The pollster reported that Democrat Mark R. Warner has widened his lead over Republican Jim Gilmore in Virginia's Senate race.

In a June 12 telephone poll of 500 Virginia voters, 45 percent backed Obama, the presumptive Democratic presidential nominee, while 44 percent supported McCain, the likely Republican presidential nominee.

Last month, when Sen. Hillary Rodham Clinton was still vying for the Democratic nomination, 47 percent backed McCain and 44 percent supported Obama, according to Rasmussen, an independent polling operation that publishes online. Virginia has not cast a majority of its votes for a Democratic presidential nominee since President Lyndon B. Johnson in 1964.

"If the election were held today in Virginia, the presidential race would be a squeaker," said Larry J. Sabato, University of Virginia political analyst. "Some of McCain's people are overconfident. They're putting too much emphasis on the historical trends in Virginia.

"This is a different kind of year, and the electorate may be structured differently. Democrats are enthusiastic, and Republicans are in the doldrums."

Five percent of Virginia voters favor a third-party candidate, and 7 percent are undecided, the survey showed.

For most people, the vice presidential choice matters little, Sabato said.

"By November, the vice president choice will make almost no difference expect in maybe the home state or maybe not even that," he said. "That's traditional."

Three of the state's top Democrats have been mentioned as possible Obama running mates -- Gov. Timothy M. Kaine, a national co-chairman of the Obama campaign and an early Obama supporter, Sen. Jim Webb and Warner.

About half of Virginia voters rate Kaine's job performance as good or excellent, but 35 percent said they would be less likely to vote for Obama if Kaine were his running mate, according to the survey. A quarter of voters said they would be more likely to vote for Obama because of it. Thirty-six percent said it didn't matter.

Charlie Kelly, executive director of Kaine's political action committee, Moving Virginia Forward, said Kaine is focused on state business, such as the legislature's upcoming special session on transportation, but that he's doing what he can to make sure Obama wins the state in November.

If Obama picked Webb, 23 percent of voters would be more likely to vote for Obama, while 32 percent would be less likely to vote for him, the survey showed. Neither Webb nor Kaine has publicly put much stock in their chances.

Warner distanced himself from the possibility over the weekend, saying he is committed "110 percent" to winning the Senate seat.

The latest survey from Rasmussen Reports shows that Warner is expanding his lead over Gilmore, leading 60 percent to 33 percent. The two former governors are vying to succeed Sen. John W. Warner, R-Va., who is retiring.

Those numbers, Sabato said, are not surprising.

"I literally know not a single political analyst in the country who is doing anything other than guessing how big a landslide Mark Warner will have."

Rasmussen Reports surveyed 500 likely voters on June 12. The margin of sampling error ranged from plus or minus 3 percentage points to plus or minus 4 percentage points.

Contact Olympia Meola at (804) 649-6812 or omeola@timesdispatch.com.