Election 2008: Southern swing state update

With Sen. John McCain's speech a wrap, the eight-week battle for the presidency is underway. Here's an update on what Southern states might be in play.

The polls all show that, in the South, it's down to three states: Florida, North Carolina and most importantly, Virginia. A quick look at the situation in each state:

VIRGINIA: The biggest Southern battleground. Averaging the latest polls, RealClearPolitics has VA in a dead heat, with McCain and Obama both at 46%. Pollster gives Obama a very slight edge in its trend analysis, and its true the momentum clearly appears to be in Obama's direction. Nate Silver at 538.com also gives Obama an edge in Virginia; his formulation gives Obama a 63% chance of winning the state.

Virginia also rates as the 3rd-most important swing state on two of Silver's yardsticks: the "Tipping Point" scale -- how often the state tips the election one way or another in a simulated race -- and the "Return on Investment Index," which factors how valuable it is for either campaign to put resources into the state.

NORTH CAROLINA: Obama is keeping N.C. close, but the averages at RealClearPolitics show that McCain is holding the state just out of reach with a 4.2 point lead in the last five polls. Pollster shows it slightly closer, and also notes the "X Factor" in N.C.: Libertarian candidate Bob Barr, who's running at 3.9% in the state.

Silver at 538.com gives McCain a 68% chance of winning North Carolina. His simulations also show N.C. tipping the election 6% of the time -- making it the 9th-most vital swing state -- but it ranks low on the "Return on Investment Index."

FLORIDA: A big swing state in 2000 and 2004, Florida is proving harder for the Dems this time around. RealClearPolitics has McCain up 3.4% in Florida in its poll averages. Pollster again has it a little tighter -- and perhaps most importantly, shows Obama gaining ground.

As for 538.com, Florida ranks as a pretty important swing state -- it tips the election in 13% of Silver's simulations, 5th-most in the country. But is also has a low return on investment, and Silver gives McCain a 63% chance of winning the state.

But the tight race, combined with Obama's momentum -- plus the Bob Barr factor -- has lead Congressional Quarterly to say there's no clear favorite.

Steadily falling from the list: Georgia. RealClearPolitics and Pollster both show McCain up about 6% here, and 538.com gives McCain an 85% chance of winning the state. And Bob Barr isn't getting any home state advantage -- Barr's numbers are going down in G.A.