Killing the vote. Photo: Erik Pendzich/REX/Shutterstock

Republicans have long known that millennials were going to be a problem for their party. The only questions were “How big?” and “How soon?”

The bulk of Americans born between 1981 and 1996 saw Bill Clinton preside over an age of (relative) peace and prosperity — and then George W. Bush steer their nation into failed wars and economic collapse. Political science research suggests that a voter’s partisan preferences tend to be deeply informed by their evaluations of presidential performance in adolescence and early adulthood. Americans who came of age during the Kennedy, Johnson, and Nixon presidencies leaned Democratic for years after. Those who attained a sense of self amid Jimmy Carter’s losing battle against stagflation — and/or Ronald Reagan’s boom times — remained disproportionately Republican as they aged.

Thus, millennials were likely to lean left, even if their generation wasn’t more diverse, highly educated, and atheistic than its predecessors. But it is. And since all of those traits correlate with ideological liberalism (broadly defined), it’s none too surprising that millennials are far more progressive in their policy preferences — on virtually all issues — than their parents or grandparents.

So, the problem for the GOP has been clear. And for a moment there, Barack Obama’s 2008 election appeared to confirm that said problem was massive: As the “emerging Democratic majority” continued to emerge, the Republican Party would need to move left, or accept a rapidly declining share of the vote. After all, by 2014, virtually all millennials would attain voting age.

Of course, reports of the conservative movement’s impending death were greatly exaggerated. In fact, the first two elections in which (virtually) all millennials could vote would first give Mitch McConnell control of the Senate, and then Donald Trump command of the White House.

The reasons for the right’s revival are too myriad to comprehensively catalogue here. But two important ones were that millennials voted at woefully low rates, and the boomer generation shifted (even further) right.

That first development wasn’t really a surprise. Younger Americans have always tended to be less-than-diligent about civic participation. The 2014 elections were the third midterms for which at least some millennials were eligible to vote. And while their turnout rate was an abysmal 22 percent that year, Generation X’s showing in its third midterm (1998) wasn’t much better. So, even after the disappointment of 2014 and 2016, it was still possible to believe that my generation would one day enter the electorate en masse — and promptly lay waste to the Republican Party. As the pollster William Jordan wrote in 2017:

[A] voter stops being under-represented in the electorate at about age 40 — which is the age of some of the oldest Millennials in around 2022 … It’s not obvious that the Millennial Reckoning will come in 2018, or even 2020. That said, based on data from past elections, it’s when a cohort starts to nudge up against their fourth or fifth presidential election cycle that they start seeing real improvements in turnout rates — and that’s about where Millennials are now. Looking just at how Boomers and Gen-Xers behaved around a similar time, we’d expect Millennial turnout to increase by around 5 or 6 points between 2016 and 2020.

We haven’t yet seen what it looks like when Millennials come into their own as a voting bloc, and it will almost certainly happen. The only question is, will it happen gradually, or suddenly? Is there anything going on in American politics that might spur an unusual lurch forward among the nation’s youngest, most diverse and most educated generation?

It is now clear that Donald Trump’s election spurred just such “an unusual lurch.” On Wednesday, Pew Research released a report on voter turnout in the 2018 elections, and its analysis of Census Bureau data shows that millennial turnout surged to 42 percent, a full 20 percentage points higher than the cohort’s rate in 2014.

And yet, that might not actually be the report’s most ominous finding for the GOP. The first time any Gen-Xers were eligible to vote in a midterm election, 23 percent of them showed up at the polls. The oldest millennials posted that same rate in 2006. But in 2018, voting-age Gen-Zers — who, by all appearances, are every bit as left wing as millennials are — put up 30 percent. And since voting is habit, that strong initial showing puts Gen Z on track to punch above its (age-adjusted) weight for elections to come.

Collectively, in 2018, millennial, Gen-Z, and Gen-X voters cast more ballots than boomers or “silent types” for the first time ever in a midterm election. Exit polls suggest that Democratic candidates won 58 percent of voters between 30 and 44 last year, and 67 percent of voters under 30, even as they essentially tied Republicans among voters 45 and up. Which suggests that an ostensibly Trump-inspired acceleration in the political maturation of millennials and Gen-Zers played a major role in painting the House map blue last year.

All this bodes well for Democrats in 2020. After all, between last year’s midterms and next year’s judgment day, millions more Gen-Zers will become eligible to vote. And the older millennials get, the more likely to vote they become, irrespective of external political conditions. Meanwhile, there were 8.8 million fewer members of the boomer and silent generations eligible to vote in 2018 than there were in 2014, largely due to mortality. Which is to say: Trump eked out an Electoral College majority in 2016 on the strength of overwhelming support among demographics that will be considerably smaller in 2020.

All that said, Democrats still can’t quite bank on their “emerging majority.” Turnout among younger voters did spike last year — but turnout among older ones did, too. Remarkably, even though there were nearly 9 million fewer boomers and silent voters walking the earth in 2018 than in 2014, these generations nevertheless cast 3.6 million more ballots in the latter year, as they turned out at a record 64 percent rate.

This enthusiasm among older voters — combined with their steady rightward trend in recent years — could sustain Trump’s Electoral College majority in 2020. And if the oldest Gen-Xers follow the boomers’ example, and shift right as they enter their golden years, then the GOP may not confront a major demographic crisis for a long time if ever. The critical question is whether each generation’s current political views will prove durable, or whether all will grow more conservative with age. If the former is true, the GOP is in deep trouble. If the latter is, then demographic trends could actually benefit the Republican Party: Boomers will be a declining share of the electorate in the years to come, but senior citizens will be a growing one. Barring massive changes in immigration policy, America is going to become an ever-older country in the decades ahead.

The boomers’ right turn in recent years complicates the body of political science literature that suggests voters don’t become more conservative as they age, but it doesn’t necessarily contradict that research. The boomer generation as a whole could be growing more conservative, even if individual boomers aren’t — because less affluent, and thus, more left-leaning boomers tend to die younger than wealthy ones. Further, to the extent individual boomers are drifting toward Republicans, this may have less to do with their aging than it does with the rising salience of immigration in American politics. On that specific issue, older, less diverse generations throughout the Western world have long leaned right. Notably, after centering issues of immigration and diversity in 2016, Democrats campaigned narrowly on health care in 2018, and drastically improved their performance among boomer voters.

In sum: If late-life reality doesn’t bite Generation X hard enough to turn those slackers into reactionaries — and if swing-voting boomers start worrying more about prescription costs than Central American migrants — millennials and Gen-Zers could make the conservative movement noncompetitive in national elections as soon as 2020.