Ambinder thinks it’s Bush’s doing:

A potential objection: that old canard, that young people are liberal and become more conservative? The historical data doesn’t support it. When Bill Clinton was elected, a plurality of people under 30 identified themselves as Republicans. Same thing when Ronald Reagan was elected.

Politically, today’s cohort of 18-to-29 year olds came of age during the Bush presidency. It has turned them into Democrats.

Many thought that Kerry losing in 2004 had a significant silver lining. We may be seeing that in action here. Apparently kids don’t want to identify with that level of incompetence. The Republicans will have to seriously redefine themselves if they want this group back, but can they after supporting this guy nearly lockstep for the past 8 years?

Politics Republicans Losing Party ID Fight