This is not the first election of the backlash. A deep-blue district in Delaware was won by a Republican by a margin of some 30% in a recent special election.
The race to fill Thurman Adams' Senate seat was much more complicated than that. His daughter's loss to the Republican House member was more of a backlash against the Dem powers that be for playing dirty pool than anything to do with a backlash against Obama. The Bridgeville area is pretty conservative, as was Thurman.