Nate Silver homes in on one Gallup question:
... the popularity -- or lack thereof -- of the President when the voter turned 18 would seem to have a lot of explanatory power for how their politics turned out later on...[T]his points toward the idea that partisan identification -- while not exactly being "hard-wired" -- can be quite persistent as the voter moves through her lifecourse. Voters who came of age during the eight years of the Bush Presidency are roughly eight points more Democratic than the rest of the country; that advantage could be worth an extra point or two to Democrats throughout the next half-century.
Republicanism has been branded as toxic in the imagination of a generation. That won't end soon. And if Obama manages to engineer an economic recovery that lasts ... then the retrospective could hurt the GOP for the rest of our lifetime. Rove will have managed the durable majority he long sought - for the Dems.