Here is what the first-term congressman did, based on public reports and allegations in the challenge: In advance of the riot at the Capitol, he met with planners of the demonstrations and tweeted that “the future of this Republic hinges on the actions of a solitary few … It’s time to fight.” He spoke at the pre-attack rally at the Ellipse, near the White House, where he helped work the crowd into frenzy, saying the crowd had “some fight in it” and that the Democrats were trying to silence them. And in the aftermath of the mob violence, he extolled the rioters as “political hostages” and “political prisoners,” and suggested that if he knew where they were incarcerated, he would like to “bust them out.”

The constitutional term “insurrection” is less cut-and-dried than, say, whether a candidate is 25 years old. In other contexts, courts have defined it as a usually violent uprising by a group or movement acting for the purpose of overthrowing the legitimately constituted government and seizing its powers. That accurately describes the collective pro-Trump effort to undermine the certification of the November 2020 election.

In the hours after the riot, Mitch McConnell, then the Senate majority leader, described the attack as a “failed insurrection”; one of President Trump’s own lawyers in the impeachment trial stated that “everyone agrees” there was a “violent insurrection”; and Mr. Cawthorn himself voted for a resolution that described the attackers as “insurrectionists.” He’ll be hard pressed to run from that label now.