Protesters-turned-rioters who massed at the Capitol on Jan. 6 carried with them pro-Trump signs, American flags and an array of political banners. Some waved Marine Corps flags; some sported military and tactical material. More than two dozen people who were later charged in crimes stemming from the attack on the Capitol had military ties. One veteran was accused of being the leader of the far-right, anti-government extremist group Oath Keepers. For decades, the U.S. military has sought out extremists such as militia groups, white supremacists, skin heads and others who advocate violence against the government. But the Defense Department has no method of tracking allegations of extremism.

The concerns were evident long before the attack on the Capitol. 25 years ago, then-Army Secretary Togo West ordered an army-wide investigation of subversives by a special task force he appointed. A two-month inquiry found only isolated cases of extremism in the ranks. West convened the task force following the 1995 murders by 82nd Airborne Division paratroopers of a black couple in Fayetteville. Police concluded the three white soldiers who were charged in the killings were skin heads with racial motives. The task force said many soldiers reported "an undercurrent of subtle racism" which focused on racial, ethnic and cultural differences.