Now it is just a bunch of crap. Originally defined the 'combatants' as lawful, unlawful and non.
Saw a Red Cross doc ironically with similar. Point being, lawful combatants have a state sanction, wear easily identifiable uniforms etc. Unlawful combatants ie. those participating in warfare without a state sanction can be killed on the field whenever found or captured and tried as the country sees fit. All these folks (whether treasonous, seditious, Hatch Act) types are engaging without the sanction of their home country. Therefore, despite their motives or because of them they are unlawfully participating. This I believe is the point of the question to Judge Kavanaugh by Graham.
thanx.