One small point, before the fireworks resume:

Quote Originally Posted by Kadagar_AV
US troops murdered thousands of people (terrorists, of course) and tens of thousands had to flee.
By definition, 'troops' cannot 'murder', only kill. Being a troop (or having been one), I'd have thought you understood that essential bit of the social contract between soldiers and their citizenry.

On the other hand, and back on-topic: Mercs, in my AO (if I were in charge) would be expelled, or apprehended, or otherwise neutralized, as 'non-national combatents'. They, by definition, interfere not only with the tactics on the ground, but also with the essential social contract I cited above.

In the Iraq case, they are a holdover from Rummie's "war on the cheap" policy. Gen Petreaus should toss them out of the country, the same as he would a Syrian with an RPG.