Democrats hope that young Obama enthusiasts will maintain their overwhelmingly liberal orientation even as they grow older and their life circumstances change. …

That conclusion, however, contradicts the evidence of 40 years of exit polls. In 11 presidential elections since 1972, voters over 65 have voted more Republican than voters under 30 in every contest but one (1988, for some reason). In none of the 11 elections did young voters tilt more Republican than the overall electorate; their levels of support for Democratic candidates in each campaign topped those of the general electorate by an average of five points.

These figures conclusively rebut the progressive hope that youthful liberals generally maintain their fervent commitment to liberalism as they age and mature. The voters who lean Republican in middle age and beyond are the same people, after all, who leaned Democratic in their younger years. For all their diabolical cleverness, Karl Rove and other cunning conservatives haven’t yet developed a scheme for creating new voters in a lab who emerge pre-aged to a seasoned 65 with an unstoppable instinct to vote for members of the Bush family.