Check out paragraph 81 of the indictment. One of his co-conspirators was having a discussion with a lawyer; the lawyer said staying in office past January 20 would trigger “riots in every major city in the United States, and the co-conspirator replied, “Well, [lawyer], that’s why there’s an Insurrection Act”.
Fortunately it looks like the federal courts don’t allow this any more: https://www.ussc.gov/about/news/press-releases/april-17-2024
But of course the state courts have their own separate rules.