But turnout and demographics don’t win elections by themselves; variant outcomes also track to a striking degree to differences in strategy. Candidates who ran as liberal Democrats rather than more traditional “Blue Dog” campaigns outperformed their more moderate counterparts in terms of base turnout. This sharper partisan appeal has allowed them to come close to equalizing the partisan composition of the district. Like their more liberal counterparts, Blue Dog candidates still experienced large turnout surges among independents. But the winning margins they enjoyed proved to be tighter than those in districts featuring Democratic candidates who saw their party hit the same percentage level—in a larger pool of Democratic coalition voters—that Republican turnout had.

This suggests these candidates may have paid a penalty by not focusing more effort on increasing turnout among their own voters and concentrating instead on independent and even opposition-party voters. This strategic choice is framed, in part, by the idea that consciously downplaying signs of Democratic affiliation will avoid upsetting Trump voters, and thereby will not inflate GOP turnout. But the data shows that Republican turnout surged in these Blue Dog districts, while Democratic turnout lagged compared to levels in other districts. In other words, my research suggests that there may be no benefit, only cost, to such a strategy.

To hear many Democratic leaders tell it, ignoring Trump was the secret to their success in 2018, but the voter file data suggests otherwise. Democratic gains, strong though they were, may actually have been handicapped by a strategy that failed to exploit the party’s best asset: the electorate’s angst about Trump. What’s more, the turnout of the Republican base was just as strong in these districts as in districts where candidates were more liberal and did talk about Trump. So the strategy of not rousing any partisan blowback in the general election doesn’t appear to have yielded the advantage of a suppressed opposition vote.

However, one party did frame 2018 as a referendum on Trump—and it wasn’t the Democrats. Again disregarding every traditional piece of conventional wisdom for presidential conduct in a midterm, Trump leaned into the referendum effect. While Democrats all but disowned Obama in 2010 and 2014, Republicans hugged Trump closely—in no small part, of course, because they were given little choice in the matter. Trump rallied for 36 GOP House and Senate candidates and tweeted about an “invasion” staged by caravans of immigrants approaching the country’s southern border, deep-state coups, and Russia witch hunts. He also exhorted his supporters to remember that he was on the ballot.

This looked to be a recipe for disaster, and it should have been, according to traditional campaign models. But Republican turnout in 2018 actually improved over the party’s 2014 turnout, even though the GOP controlled all three branches of government. The punditocracy’s fable of a key corps of disaffected Republicans breaking for the Democrats in 2018 is wrong—in much the same way that Nancy Pelosi is mistaken in her narrative of health care pragmatism swelling the blue wave. Republicans delivered for Donald Trump, as Donald Trump instructed them to. They were simply outnumbered in certain places—and almost everywhere they were outnumbered, they lost because of the turnout surge within the Democratic voting coalition.

What do all these negative partisan trends portend for 2020? Even though most analysts continue to look at 2016 as a frame for 2020, that reflex bespeaks another failure to size up a dramatically shifting electorate. The complacent voting ranks of 2016 who believed (at the energetic prompting of polls and pundit forecasts) that Donald Trump could never be president have been replaced by the terrified electorate of 2020. These voters know all too well the hazards of granting great power to a figure like Trump and view the president as a Terminator-like political figure who simply can’t be stopped. After threading the 2016 Electoral College needle, Trump has acquired an almost mythic aura of invincibility for most people, election analysts included. And in some key ways, the unsettled character of this political moment—together with the structural inequities of the Electoral College and a battery of GOP-orchestrated voter suppression drives—has inoculated President Trump from political gravity. But as Andrew Yang would tell you, math matters, and Trump has a basic math problem. As the electorate is currently constituted, there are more potential Democratic voters out there than there are Republican, and not just in California. There are more in the Midwest and in the Sun Belt. There are so many more in Virginia and Colorado that both states have moved off the swing state map.

The 2020 election will be a battle of the bases, with nothing less than the country’s survival as a functional democracy on the ballot. Partisanship is a hell of a drug—especially when it’s cut with a heavy dose of existential fear.