Matt Bai seems to suggest that they should:
bq. What’s more, as some of the sharper Democratic strategists have realized, reaching voters down South isn’t only about the South. Culturally and ideologically, there isn’t much that separates most Southern, independent white voters from those who live in exurban Ohio or in rural Missouri. (It was the native Southerner James Carville who famously observed that Pennsylvania was, for all practical purposes, just Alabama sandwiched in between Philadelphia and Pittsburgh.) If Democrats want to win those perennial swing states by anything other than the tiniest of margins, then they will probably have to put forth the kind of candidate and argument that will also resonate in much of the South, whether they care about the region or not.
Yes, it’s true that voters in the South are not necessarily different from voters in other places, and thus a particular Democratic candidate and message may be effective in both the South and elsewhere. But that’s not the issue. The issue is whether it makes sense for the Democrats to spend resources — that is to say, buy advertising time, send direct mail, mobilize voters, etc. — in Southern states, regardless of their message or candidate. In a system where the winner is determined by winner-take-all state-level battles for Electoral College votes, it’s far from clear that the marginal return on finite Democratic campaign dollars is large enough in Southern states, relative to the traditional battleground states, to justify the expenditure. Perhaps the landscape in 2008 will show significant potential for the Democratic nominee in some Southern states, but whatever the case, decisions about the nominee’s message and decisions about resource allocation are quite distinct — a fact that Bai elides.