Earlier quoted context omitted.
The US military is made up of professional soldiers. Citizen soldiers are citizens first, and soldiers only when civic duty calls them up.
That's pretty much describing the vast bulk of US military. Citizen Soldiers.
Active duty personnel cannot be considered citizen soldiers because their service is not compulsory and they are full-time professionals, not merely civilians in service.
Reservists might be considered citizen soldiers, if you're a bit loose with the criteria that service must be a compulsory civic duty.