If you don’t believe my constant assertions that “midterm falloff” is a problem that preceded the Obama Era but emerged as a bigger problem for Democrats when young and minority voters became a larger part of their coalition, check out Geoffrey Skelley’s analysis of voting by age at Larry Sabato’s Crystal Ball.
According to Skelley’s numbers, the “midterm falloff” in the percentage of the electorate comprised of under-30 votes from the preceding presidential election was 9.5% in 1978, 8.0% in 1982, 7.8% in 1986, 6.3% in 1990, 7.6% in 1994, 3.7% in 1998, 5.7% in 2002, 4.4% in 2006, and 6.3% in 2010. You can say it’s not as bad lately as it once was, but it’s still mighty consistent. And at the same time, thanks to the aging of the Baby Boom generation, the percentage of the midterm electorate made up of over-60 voters has risen and then stayed high. In every midterm since 1994, over-60 voters have more than doubled under-30 voters as a percentage of the electorate. The gap in presidential years is vastly lower (as recently as 1992, under-30 voters still outnumbered over-60 voters).
As Skelley notes, the reasons for the age gap in midterms are not attributable to easy-to-change shortcomings in candidate or party messages:
[S]harply lower young voter participation in midterm elections is surely a trend that predates national exit polls. Older people are simply more likely to vote in general due to a number of lifestyle factors, such as buying a house, starting a family and becoming settled in a community. Even when the 18-to-29 cohort made up a plurality (30.4%) of the country’s adult population in 1980 (the last time that was true as the Baby Boomers got older), the 1982 midterm election saw an eight-point drop in that group’s portion of the electorate from the 1980 presidential election, falling from 22.9% to 14.9%.
There are, however, low-falloff years, such as 1998 (when Democrats broke the rules by making gains in a second-term midtern) and 2006 (when Democrats ran the table). Those should be the models for Democrats this year, when they depend on young voters more than at any time in memory.