President Trump counts on getting voters to nurture and express their ugliest feelings. Yet so far, in one of the most important but underappreciated developments of the 2020 presidential campaign, he seems to have completely failed at persuading Republican voters to truly despise Joe Biden.

They certainly don’t like Biden. But they don’t detest him with the kind of burning fire that Hillary Clinton inspired in them four years ago. And that’s a serious problem for a president who depends on anger and hatred to motivate his supporters.

When Trump held a news conference Tuesday and blathered on for nearly an hour, mentioning Biden no fewer than 31 times (among other things, he claimed Biden would “abolish the suburbs”), it may have been because aides have urged him to talk more about the presumptive Democratic nominee. Their theory, no doubt accurate, is that if the election is just about the president, he’ll lose.

But so far, nothing the Trump campaign has tried has turned voters against Biden. Trump supporters have argued that Biden is corrupt, that he’s too old, that he has a bad record as a senator, and that everything that Trump has failed to do is actually the fault of Biden and Barack Obama. It hasn’t made a difference; Biden still has a wide lead in just about every poll.

They’ve given up on trying to claim that Biden is some kind of left-wing extremist; now they argue that he’ll merely be a puppet of the “radical left.” For instance, this Trump ad portrays a hellscape of chaos and violence brought by “the radical left-wing mob’s agenda ... and Joe Biden stands with them.” The campaign has already spent millions airing the ad, to no evident effect.

So what’s the problem? You can explain it in any number of ways. Biden is familiar from his many years as a senator and vice president, which makes it harder to change how people think of him. Uncle Joe may be a little overbearing at times and say things he shouldn’t, but everyone knows he means well. You may find him occasionally exasperating, but you don’t hate him.

And unlike Clinton, he isn’t a woman, so he doesn’t bring out the same kind of venomous misogyny she did. Nor has he been the target of decades of attacks from the right, the way she was.

It’s almost impossible to overstate just how much Republicans hated Clinton — and how important that was in 2016.

Let’s take just one measure. For decades, the highly respected American National Election Studies has been asking voters to rate candidates on a “feeling thermometer." In 2000, Republicans gave Al Gore an average thermometer rating of 41 out of 100. In 2008, they gave Obama an average rating of 37. Their average rating for Clinton in 2016 was 17.

That’s partly a result of polarization and negative partisanship (ratings for the other party’s candidate have been steadily declining for the past two decades), but it has a lot to do with Clinton herself. Trump’s victory in 2016 — losing by 3 million votes but squeaking out a win in the electoral college — was only possible because so many Republicans hated Clinton so much that they were able to put aside their reservations about Trump.

Two months before the 2016 election, Michael Anton penned an influential pseudonymous essay entitled “The Flight 93 Election.” The prospect of Clinton becoming president, he wrote, was so terrifying, so cataclysmic, so certain to result in the end of all that was good about America, that whatever their hesitancy about Trump, conservatives simply had to “charge the cockpit” and get him elected.

Today Anton’s essay reads as both ludicrous and repugnant in a dozen ways (among other things, he lamented “the ceaseless importation of Third World foreigners with no tradition of, taste for, or experience in liberty”). But today, no Republican tries to make the same kind of case, despite the fact that Biden is running on a far more progressive platform than Clinton did. Republicans just can’t seem to work themselves up into the same frenzy of terror and loathing.

Which shows how much of what they felt in 2016 was personal, not about what Clinton would do in office. Not only that, with the Trump presidency being such a disaster, no Republican can tell themselves, as they did then, “Sure, he’s a bigot and a buffoon. But maybe it will be fine.”

And you know who is motivated by hate right now? Democrats. As political scientist Michael Tesler notes, in some polls, the proportion of Trump voters who have highly unfavorable opinions of Biden trails the proportion of Biden voters with highly unfavorable opinions of Trump by nearly 30 points.

The Trump campaign likes to talk about the “enthusiasm gap,” by which it means that Trump has more intense supporters than Biden. But this is the enthusiasm gap that matters. A voter who finds Biden simply tolerable but would crawl through fire to vote against Trump is worth just as much as a MAGA-clad devotee of the president.

There’s still time for the Trump campaign to get people to hate Biden. But so far the president’s supporters haven’t been able to do it, and we haven’t seen much to suggest they’ll figure out how.