So, which soldiers are most vulnerable? According to the Homeland Security report, it would probably be those “facing significant challenges reintegrating into their communities.” This could be a large group because far too many soldiers come back from war broken men. According to a RAND study released on Friday, 300,000 veterans of the wars in Iraq and Afghanistan reported some sign of post-traumatic stress disorder or major depression. It said that only about half of those will seek help and only half of those seeking it will receive “minimally adequate” treatment.

These soldiers could prove fertile ground for men hoping to prey on their fear, loneliness and dispossession.

And those extremist leaders may be able to connect more easily with some of these soldiers because many were soldiers themselves. According to the F.B.I. report, “although individuals with military backgrounds constitute a small percentage of white supremacist extremists, they frequently occupy leadership roles.”

Because many know firsthand the value of military experience, they not only recruit those leaving the military, they send recruits into it. According to Mark Potok of the Southern Poverty Law Center, “Many white supremacists over the years have pushed their followers to join the military and enter either the special forces, where the training is judged to be the best in the world, or the infantry, where you will learn the skills necessary to fight the coming race war.”