There does not seem to be much of a regional distinction. Lautenberg was the only incumbent Dem to run behind Obama. These incumbent Repubs ran behind McCain:
Stevens
Dole
Sununu
Coleman
Cornyn
Cochran and/or Wicker
Inhofe
Chambliss
Yeah, it looks like Republican Senatorial candidates just got clobbered this year.
Looking back at the maps, half of Republican incumbents ran behind their losing presidential nominee. The ones running ahead of McCain were:
Smith
Enzi and/or Barrasso
Roberts
Alexander
Sessions
Graham
Sununu
Collins
So 8-9 for both. Or can anyone look up the results of the WY and MS special elections?