In hearings so far, the U.S. House committee investigating the Jan. 6, 2021 attack on the U.S. Capitol by a violent, pro-Trump mob has outlined how it believes the former president and extremist groups carried out the attack that day. But Jan. 6 was the culmination of years of political violence. Oregon and other states served as a training and ideology testing ground for the groups who would go on to play leading roles in the insurrection.