Explaining Southern Republican dominance

There's an interesting discussion at Kevin Drum's Political Animal blog that boils down to this question:

Did Republican Party dominance in the South happen because suburban Southerners were attracted to Republican economic policies, or did racial politics create the Southern suburbs and make them responsive to race-baiting Republican messages?

Here is an edited version of Drum's post:

Clay Risen wrote a piece in the Boston Globe last week about a new book, The End of Southern Exceptionalism, by Richard Johnston and Byron Shafer. Johnston and Shafer argue that the reason the South became a Republican stronghold following World War II was due less to racial backlash than to the postwar growth of suburbia, with its natural affinity for Republican economic policies. ...

But perhaps this puts the cart before the horse. After all, it's not a natural law that suburbs have to be conservative, so it's worth asking why suburbia is so conservative in the first place. A few months ago Kevin Kruse sent me a copy of his book White Flight, which I just started reading over the weekend, and he argues that, in fact, suburban economic conservatism is inextricably linked with racial backlash. ...

Since I haven't finished the book I need to be careful summarizing Kruse's argument, but basically he suggests that the crude Klan-style racism that dominated attention at the national level during the postwar years was actually fairly ineffective, and was quickly replaced by more sophisticated segregationist arguments that were less overtly racist: namely that whites weren't fighting against the rights of others but for rights of their own. ...

This core set of beliefs, which was originally just an acceptable public face for private segregationist sentiment, was carried into post-WWII suburbs by whites fleeing central cities, where they found a sympathetic reception in the Republican Party. Eventually these beliefs became the bedrock economic principles of the party, and as Southern whites became increasingly influential within the GOP its economic policies became ever more radicalized.

So: was Republican ascendancy in the South due primarily to economic likemindedness or to racial backlash? Which came first, the chicken or the egg?