With Virginia's Election Day less than 48 hours away, large numbers of previously undecided voters say they're supporting Bob McDonnell for governor, giving the Republican a 12-percentage-point lead over Democrat Creigh Deeds, according to a poll.

McDonnell consistently has been ahead of Deeds in voter surveys and was supported by 53 percent of likely voters polled Wednesday and Thursday compared to 41 percent who favor Deeds, according to Mason-Dixon Polling and Research Inc. Six percent were undecided.

The phone survey of 625 registered voters who plan to vote Tuesday has a margin of error of plus or minus 4 percentage points.

Support for Deeds was relatively unchanged from a Mason-Dixon poll taken Oct. 6-9. However, McDonnell's support has risen and the number of voters that remains undecided shrank by half.

President Barack Obama's speech at a rally for Deeds in Norfolk on Tuesday, which the campaign hoped would energize voters, didn't seem to have an effect, said Brad Coker, managing director of Mason-Dixon.

"McDonnell's lead... does not appear to have been dented in any way by Obama's appearance," Coker wrote in his analysis.

Instead, McDonnell, a former state legislator from Virginia Beach, made his strongest gains among likely Hampton Roads voters, according to the poll. He also appears to be leading Deeds in most regions of the state except Northern Virginia, where Deeds had a slight edge.

Deeds, a state senator from Bath County, has counted on strong support in the Washington suburbs and Hampton Roads as well as his native western Virginia. The two populous regions were key to Obama's carrying Virginia last year and the election of Gov. Timothy M. Kaine, a Democrat, in 2005.

While both gubernatorial candidates had overwhelming support from voters from their parties, McDonnell made gains among independent voters, according to the poll.

Swaying the independents can be critical, Mason-

Dixon's Coker said. Democrats Mark Warner and Kaine won the governorship with their support in 2001 and 2005, respectively.

Coker also noted that Deeds' campaign was having trouble attracting enough women and black voters - two groups key to a statewide Democratic win.

Men tended to support McDonnell by almost 2-to- 1 while women were split, the poll found.

Deeds "has no margin with women," Coker said.

As for black voters, fewer than one in 10 polled said they would support McDonnell, although an almost equal number was undecided - as they were three weeks ago.

"What you see is a lack of excitement there," Coker said. "This tells me they're not going to turn out."

Four years ago, when Deeds and McDonnell went head to head in the state attorney general's race, Deeds was behind in polls. The election was very close, however, with McDonnell winning by 360 votes out of 1.94 million.

But four years ago, the margins were much tighter. In the days before that election, Mason-Dixon reported that McDonnell was supported by 43 percent, Deeds by 40 percent and 17 percent were undecided.

 Bill Bartel, (757) 446-2398, bill.bartel@pilotonline.com