Republicans have a problem with young people 18-29. Democrats have a problem with seniors over 65. The story taken from this dichotomy is popular and simple enough: Republicans are the party of crusty old folks who are going to die, and Democrats are the party of the youth, who will lead a continued resurgence into office.
I'm not so sure about this story; the generational math is different than you might think.
One of my favorite bits of trivia points to the bigger picture: "From which age group did Bill Clinton win the highest percentage of votes in 1992?"
Indeed, if you came of age during the Franklin D Roosevelt administration, you are more Democratic than the nation as a whole. If you could first vote during the administrations of Ronald Reagan or George HW Bush, you're more Republican. Turn 18 while George W Bush or Barack Obama held the White House and, again, you're more Democratic. That's right: the 18-29 year-olds of today are about as Democratic as their oldest grandparents and great-grandparents.
These voting patterns tend to stay relatively consistent within a group, even as people age. Contrary to popular belief, people don't become any more conservative with every birthday, and college doesn't necessarily make people more liberal.
There are two key questions, then: who's next to die off, and what ideology will their successors have?
Most people part of the Eisenhower/Truman-generation, who vote more Republican than the nation at large, are likely to be around through the next three elections; estimates suggest life expectancies of about 9-16 years for people aged 80 to 70. Voters of the very Democratic Roosevelt-generation have life expectancies of less than eight years, being at least 85. Thus, the generations most likely to expire next are those who have historically been more Democratic.
Many might think that these Roosevelt-generation voters are going to be replaced by more liberal Obama-era voters, but polling casts that theory into doubt. Just because today's college students are liberal doesn't mean tomorrow's will lean left, too.
UCLA has been polling freshman college students for over 40 years on their political beliefs, and has found that young people are hardly automatic Democrats.
On the eve of the 2008 election (pdf), the most college freshmen in 35 years – 30.3% of men and 37.4% of women – described themselves as liberal or left. Combined, that matches the 33% percentage of 18-29 year-olds who described themselves as liberals in 2012. In other words, the new college students of 2008 were representative of a new generation of liberals.
On the eve of the 2012 election, the percentages of liberals among first-year college men and women dropped by 4pt and 5pt, to 26.4% and 32.4%, respectively. The liberal percentage is about 10pt higher than it was during the Reagan administration (pdf), but it's a major liberal decline – nearly on par with what occurred between the 1976 and 1980 elections.
New college students are liberal – just not as liberal as freshmen were four years ago. This new class is about as liberal as young people were early in the Carter and Clinton administrations. People who turned 18 during the Carter administration ended up being somewhat more Republican than average; those who came of age during Clinton's were somewhat more Democratic. How today's college freshmen will vote likely depends on the state of the economy over the next four years.
Are the new college freshmen just a blip in a sea of student liberalism?
The polling says "probably not". Before the election, American University/GfK polled high school (13-17 year-olds) and college students. The margin between Obama and Mitt Romney for high school students was 21pt less than among all college students. (Note: there's no discernible difference between the voting patterns of 18-29 year-olds with at least some college education and those without.)
The huge fall isn't exactly surprising. The Roosevelt generation is liberal because people became politically aware when Roosevelt was viewed as a success. The Gipper generation is conservative for the same reason with regard to Reagan. Conversely, the younger Bush is mostly viewed as a failure, and as such, most young people revolted.
Obama's presidency, meanwhile, is only seen as a moderate success – as illustrated by a rather close re-election margin in the popular vote. Given past history, it's expected to be seen as somewhere between good and average, as far as presidencies go. We would expect, therefore, that people who come of age during this presidency to be about as Democratic as the nation, or slightly more so.
And that's exactly what seems to be happening.
Indeed, the generation of the next few years isn't likely to be either conservative or overwhelmingly liberal; it's probably going to be moderate. The UCLA survey found that the fastest growing group are people who describe themselves as "middle of the road". On social issues, like gay marriage, they lean lean to left; on fiscal issues, like healthcare, they lean more to the right than the majority of current 18-29 year-olds.
Overall, I doubt we're looking at a pipeline of new liberals. Far more than most young voters today, the next generation is likely to be up for grabs.