Nate Silver at fivethirtyeight.com has an interesting post about political identity and the President in office when a person turns 18. There appears to be a reasonably significant correlation between a person’s political affiliation and the President in office when the person turned 18.
A good President in office tends to correlate with a person’s identification with that President’s political party, apparently for a lifetime. And a bad President tends to correlate with identification with the opposite political party. Correlation doesn’t equal causation and all of that, but Nate Silver’s hypothesis is that Bush’s exceptional badness might haunt the Republicans for generations to come (much as they have had ongoing benefits, generally, from Reagan’s tenure.)