Please don't use the term "mercs" for contractors. Mercenaries are hired to fight for a foreign government or entity. Almost all the contractors working OCONUS are either skilled laborers, supervisors, security, advisors, or trainers. There is a very strict ROE for contractors that does not allow any fighting except in defense of person or US property. Although used in past wars by the US, mercenaries have been done away with by the US after the fall of Executive Outcomes in the 90s. Yes, even Blackwater in 04-05 was not ordered to fight unless in defense.