Nate Silver dismisses the partisan split:
...partisan identification is at least somewhat fluid. The Republicans, in particular, have lost quite a bit of support over the past several years; those persons who continue to identify as Republicans are a hardened -- and very conservative -- lot. Just 24 percent of voters identified as Republican when Pew conducted this survey in March, which is roughly as low as that total has ever gotten.
2006-2011 archives for The Daily Dish, featuring Andrew Sullivan