Senator Ron Johnson of Wisconsin has been on the forefront of elevating fringe theories about President Biden’s son Hunter, the coronavirus and the results of the 2020 election.

In recent weeks he has come under renewed scrutiny for claiming in a series of radio interviews in his home state that the Jan. 6 attack on the Capitol was not an “armed insurrection” and for using his time during a Senate hearing to read a first-person account that posited “provocateurs” and “fake Trump supporters” were behind the attack.