Oath Keeper pleads guilty to seditious conspiracy as pressure intensifies against right-wing extremist group

"We must win. We must defeat these radicals" Ulrich wrote in one text, "there's treason at work here. When someone committed treason it used to mean something. you used to pay with your life!"

According to the plea agreement, Ulrich, 44, will cooperate with the Justice Department in its historic prosecution against the far-right extremist organization. He could face more than six years in prison, according to the deal read aloud during Wednesday's hearing, but prosecutors may ask for a lower sentence depending on Ulrich's level of cooperation.

The guilty plea is another major step in the criminal case against the Oath Keepers, as prosecutors work to show how they believe the group of men plotted to stash weapons across the Potomac River, go to the Capitol and stop Congress' certification of the Electoral College vote. The case has grown dramatically over the past year, relying in part on explosive private messages between Oath Keepers leaders, video of the group from the week they were in DC, and the cooperation of at least six other Capitol riot defendants with ties to the Oath Keepers organization.