On January 6, 2021, things became very bad indeed. And the question before the country is: Will the politics of violence be accepted in the United States—or will it be punished and discredited as it was when used by anti–Vietnam War leftists and anti-civil-rights racists? The forces Trump conjured remain forces to reckon with. Hundreds of millions of firearms are housed in American garages, basements, and attics. Delusions and disinformation still flow through social media. For a long time, however, mainstream politics has been barricaded from violence not only by the moral resistance of decent people—but also by the pragmatic calculations of even cynical politicians that violence does not pay.

That pragmatic calculation has been weakening. In 2018, the present governor of Montana won a House race after he violently attacked a journalist for asking him an unwanted question. More and more politicians campaign with firearms at their side. The taboo on political violence, already weaker in the United States than in many peer democracies, is weakening further. Among other things, Trump’s impeachment trial offers an opportunity to reassert that taboo, to denormalize mayhem and murder as the route to power.

So it’s not only Trump who is on trial. It’s his methods—and all who aspire to adopt his methods as their own in the political contests ahead.