There mostly US citizens and are not under the command of the US armed forces nor are they combat troops but glorified security guards.

ITT is the only contractor which uses mainly US citizens Gawain (though I had thought Blackwater would have aswell), the others find it far more profitable to recruit from other sources , one source that has recently been tapped is the reruitment of Chilean ex-police commandos from the time of Pinochets rule , which is very nice isn't it .
As to the role of these "glorified security guards" as you put it , could you explain the logic in awarding Dyncorp a contract for training the Iraqi police , considering that in its previous contract for training police it was involved in sex-crimes , torture , abduction and human trafficing .