Apparently some congressman from Alabama named Parker Griffith has decided to switch from the Democratic Party to the Republican. At first that seemed a little odd. Yeah, he's pretty conservative for a Democrat, but despite all the pulling of hair and gnashing of these teeth these days, there's really not much chance of Republicans regaining control of the House next November. So why switch to a minority party?
My guess is that Wikipedia tells us pretty much all we need to know:
[The Alabama 5th district] last supported a Democrat for president in 1976, and George W. Bush won the district by double-digit margins in 2000 and 2004.
Due to these trends, most forecasters rated the district as a toss-up. CQ Politics forecasted the race as 'No Clear Favorite', The Cook Political Report ranked it 'Democratic Toss Up', and The Rothenberg Political Report rated it 'Pure Toss-Up'.
Griffith defeated [Wayne] Parker in a sweeping upheaval, taking 52 percent of the vote to Parker's 48 percent.
52% is a "sweeping upheaval"? Sounds more like a squeaker to me. Most likely then, Griffith is just a reverse Arlen Specter: an ideological centrist who figured that he'd most likely lose reelection in a tough midterm environment if he didn't switch. So he switched.