They are charged with "conspiracy to murder".

Federal prosecutor Jenny Durkan said: "The complaint alleges these men intended to carry out a deadly attack against our military where they should be most safe, here at home."

http://www.guardian.co.uk/world/2011/jun/23/us-men-arrested-alleged-plot

Quite right. Poor soldiers. How heinous to plot a deadly attack on them - at home, where they should be most safe.