For much of the past two years, Democratic leaders have focused, sometimes obsessively, on younger voters. Bernie Sanders has been partially responsible for this; in addition to promising a sweeping wave of youth support in 2020, his campaign has centered on issues young voters care most about: climate change, income inequality, free college, the value of democratic socialism. Part of this has been driven by the belief, backed by media reports, that younger voters helped fuel the blue wave of 2018, and are poised to lead the Democrats to similar victories in 2020—if only they can lure them from their millennial hidey-holes.

Recent events have begun to deflate that bubble. So far in 2020 primaries, voters under 30 have constituted just a small fraction of the electorate: 16% in Texas, and 11% in California and Vermont. Those low figures aren’t surprising; younger voters have long represented a declining portion of the electorate. (Even in 2018, when they turned out in high numbers, the increase was still proportionate to the overall voter surge.) Luckily for Democrats, failure to energize the youth vote—a widespread concern now that Joe Biden looks to be the likely nominee—isn’t the end of the road. Older voters are playing an increasingly determinative role in our politics. And their patterns of behavior, plus the potential implications of coronavirus, could be a very dangerous thing for Donald Trump.

It is no secret that older voters are an important bloc, but it is not widely understood how rapidly they’ve grown in importance. Fifty years ago, younger voters significantly outnumbered older voters, and even as recently as 2004, voters 65 and older barely outpolled those ages 18–29 (19% of the electorate compared to 16%). But by 2016, voters 65 and older showed up at more than twice the rate of younger voters (27% versus 13% of 18- to 29-year-olds).

There is variability in all turnout numbers, but the long-term trends all favor older voters, for two reasons. The first is simply that seniors are the most dedicated voters, averaging about 70% participation rates in presidential elections, about 6% higher than the nearest group, and almost double the voting rates of 18- to 24-year-olds. This was not always the case. In 1964, for instance, middle-age voters (those in the groups age 25–44 and 45–64) participated at higher rates than seniors, and the difference between the voting rates of the old folks (66.3%) and the young folks (50.9%) was not that significant. But since then, voting rates for senior citizens have increased gradually, while the rates for every other age group have dropped off. The transition to a voting system dominated by old people has been fueled by better health and mobility in the 65-plus cohort, but also by basic self-interest. Bob Shapiro, a political science professor at Columbia, told me that the advent of Medicare and the expansion of the senior social safety net means seniors have more at stake in federal elections than in the past. Their continued devotion to voting reflects that fact.

Seniors also play an increasing role in American politics simply because the U.S. is getting older. People over 65 now comprise roughly 16% of the U.S. population, an increase from 12.4% at around the turn of the century. By 2050, 22% of the population will be over 65. Moreover, the importance of the 65-plus vote is magnified because it’s concentrated in states that will determine the 2020 election. Florida is, of course, famously dominated by older voters, but Pennsylvania, Michigan, Ohio, and Arizona all rank high on the list of states with the highest percentages of older citizens. One Democratic strategist described the Midwest battleground states to me as “one big geriatric ward.”