Why Beliefs of 2020 Election Fraud Could Last Well Past Trump

Professor Mason said she worried that more violence and attacks on elected leaders and state Capitols could be coming, saying the country could be in for a period like the Troubles, the conflict in Northern Ireland in which sectarian violence kept the region unstable for 30 years.

In interviews with Mr. Trump’s more fervent supporters, people expressed a pattern of falsehoods and fears about the coming Biden administration. As events like the riot have raced ahead, so have conspiracy theories explaining them. They have blossomed in the exhausting monotony of coronavirus lockdowns.

Theda Kasner, 83, a retired medical worker from Marshfield, Wis., who was originally interviewed for a New York Times polling story before the election, has been in an R.V. park in Weslaco, Texas, near the border with Mexico, since December. She is spending the winter there with her husband, for the sun and the beaches nearby. But the coronavirus is roaring through, and this week, their R.V. park went on lockdown.

“I told my husband today, I said, ‘I’m going stir crazy,’” she said. “We are practically quarantined in our units.”

She has been spending lots of time in her motor home reading books and watching videos. One featured rousing, emotional music and footage of Mr. Trump and crowds of his supporters, with a voice talking darkly about a looming confrontation. It ended with the Lord’s Prayer and the date Jan. 20, 2021, flashing on the screen. Another, 48 minutes long, was of Jovan Hutton Pulitzer, an inventor, testifying before the Georgia State Senate about election fraud. She and her husband watch Newsmax TV, a right-wing network, in the evenings.

When asked about the violence at the riot, Ms. Kasner repeated the common conspiracy theory that antifa had infiltrated the crowd. These days, she is finding herself increasingly confused in a sea of information, much of it false.