Last week, in his meeting with evangelical leaders, Donald Trump unveiled what I expect will be his closing argument in this campaign, and yes, you should worry about it.

The argument is to link the idea of a Democratic victory to violence. Yes, it’s grotesque and insane, and insanely irresponsible, and all kinds of things. But it also might work.

Democrats should not underestimate this—should not underestimate, that is, the possibility that this midterm might not follow the normal script. If you haven’t been worrying too much about this, I’d advise you add it to your list.

Here’s the history. Usually in midterm elections with a president’s approval ratings underwater, his supporters are dispirited, and the other side is energized. And that’s what polls and most of the results so far are telling us.

But that’s also an atmosphere in which most incumbent presidents stay pretty quiet. By tradition, a president who knows his party is going to get pasted in the midterms doesn’t campaign, because doing so is seen as costing him political capital—the more he’s out on the stump, the more the losses can be hung around his neck, and the lamer his duckery. Hence, George W. Bush in 2006 and Barack Obama in 2010 kept low profiles as their parties’ House majorities handed the keys to the other side. They played defense.

Trump, of course, will play offense. He won’t lay low. He must be the center of attention at all times. So he’s going to be out there saying stuff; stuff that no other president would ever say about the opposition in a million years. The Bush-Karl Rove GOP went pretty far down this sleazy road with those ads that all but accused some Democrats who opposed the Iraq War of treason. But even they stopped well short of asserting that a Democratic takeover would spark violence.

Reading Trump’s remarks from last week, my guess is that he stumbled upon this somewhat by accident. First, he warned the preacher men that if the Republicans lose the House, the Democrats “will overturn everything that we’ve done, and they’ll do it quickly and violently.”

He pretty clearly meant “violently” only in a metaphorical way at first. But then it was as if something in his brain clicked upon hearing the word come out of his own mouth. A light bulb went off. So he continued: “ And violently. There is violence. When you look at Antifa—these are violent people.”

The White House declined to comment on the remark. Mike Pence was asked to clarify, but of course his words were meaningless, a bowl of sycophantic porridge. Then Trump himself elaborated a bit the next day. “I just hope there won’t be violence,” he said. “There’s a lot of unnecessary violence all over the world, but also in this country, and I don’t want to see it.”

“ It’ll work. It’ll get his base revved up to vote. Don’t think these people are going to stay home. ”

First of all, this new charge of Trump’s makes no logical sense. Why would Democrats incite violence after winning? If they were going to incite violence, wouldn’t they do so after losing?

But of course they’re not going to incite any violence at all. The only person in American politics, Democrat or Republican, who incites violence is Trump—encouraging people at his rallies to beat up protesters, suggesting that “Second Amendment people” might have a solution for Hillary Clinton. So he’s doing here what every fascistically minded leader in history has done—he’s accusing his opponents of what he does himself, so that when violence erupts, he can say “Aha! See?”

Mind you, I doubt he plotted this out. It’s all instinct with him. But this is exactly where his instinct leads him: to tell the most grotesque and authoritarian lie that pops into his head. I wrote a column back in July about the three categories of Trump lies. Category 1 is the normal misstatement of fact. Category 2 is the exaggeration (of good economic news, say). Category 3 is the factual and moral opposite of the truth.

This lie about Democrats and violence is a Category 3, and those are his favorites, so I expect he will ride this one right through to Election Day. It’s disgraceful and immoral, of course: a president of the United States revving his people up toward, at the very least, the need to steel themselves for acts of violence perpetrated against them by the other side. It’s something no other president would ever have done. But we need to be prepared for the possibility that for the next eight weeks as he goes out to those rallies, Trump is going to hit the violent Democrats button hard.

And it’ll work. It’ll get his base revved up to vote. Don’t think these people are going to stay home. The relationship between Trump and his voters is not a normal small-d democratic political relationship. It’s, ah, mystical. Plus they think you and I are evil. Not wrong. Evil. They don’t have a monopoly on that, of course, but the difference between the two sides is that they follow a racist demagogue who promotes violence and we don’t.

This is what the Republican campaign will be about: The country will descend into darkness if you give the Democrats any power. The Antifa crowd and Black Lives Matter and the haters of white people of all stripes and the child pornographers will all feel empowered. Nancy Pelosi has them all on speed dial. This isn’t a mere matter of legislation, or even of impeachment. It’s a war of culture and blood.

I still think the odds are the Democrats take back at least the House. There are some historical fates even Trump is unlikely to escape. But liberals should just be aware of the ways in which the lessons of the past might not apply here. Democracy wasn’t built for people who will tell any lie and make whatever fact-less allegation they think will help their cause. But we have one. The only antidote to him is the same one that existed in 2016: the ballot box.