Public Policy Polling has an interesting new study out that bucks the media storyline about why Barack Obama is making gains in Southern states like Florida, North Carolina and Virginia.

Obama has galvanized African-American and young voters. But what has put those states within striking distance for the Democrats is that Obama is also gaining among whites:

The conventional wisdom is that Barack Obama is doing so well this year due to the likelihood of increased turnout and support from black voters and young voters. Those things are certainly important, but a strong majority of Obama's gains relative to Democratic performance in 2004, even in the South, can be attributed to increased support from white voters.

The evidence is compelling. For example, PPP looks at Obama's strong showing in North Carolina polls. Part of that can be attributed to a boost in African-American voters, which PPP estimates will increase from 19% of the total NC electorate to 21% this year (which agrees with our analysis).

But that can only account for about 5 points of Obama's gain in NC over John Kerry's performance in 2004. The rest has come from non-black voters [pdf]:

That means Obama has picked up roughly five points based on increased black turnout and support for the Democratic candidate compared to 2004. But he's polling right now 18 points better in the state than John Kerry did. Where's all that extra support coming from? [...]

[There's a] 13 point reduction of the deficit for the Democrat among white voters compared to 2004. So while Obama's 5% increase from black voters is important, 2/3rds of his improved standing can be attributed to shifts in voting preferences among whites in North Carolina at this point.

PPP finds the same pattern in Virginia. In VA, PPP estimates [pdf] Obama has gained 16 points among whites over Kerry in 2004, and just 2 points with African-American voters.

Florida, a state with much different demographics, is a little different. Obama has gained 3 points among whites, 2 among Latinos and 2 among blacks -- according to PPP, "meaning his increased standing in Florida relative to 2004 is pretty well dispersed across racial lines in the state's electorate."

So what's pushing Southern white voters to say they might vote for Obama? PPP's analysis [pdf]:

Economy, Economy, Economy. Among white voters in North Carolina who list it as their top issue Obama is actually up 48-46. In Florida Obama has the same 48-46 lead with whites most concerned about the economy. In Virginia it's a 49-46 advantage.