Private Independent Contractors?

I personally feel contractors are a good way to provide security without wasting military manpower. Now there are those who say these contractors have an eerie merc. feel to them. I disagree, since the DoD only employs them for defensive tasks. Escort, security, and training. Im not opposed to them taking offensive actions though, would contractors taking the role as "mercs." really be that bad? Im talking CIA, Special Forces Ops where deniability and covert actions are needed. I don't think its very smart to employ private companies to fight our wars for us, but they could prove useful when talking in terms of clandestine and covert military operations behind enemy lines. Anyone who knows anything about Unconventional Warfare knows that a few guerrillas antagonizing the enemy day in and out can go a long way. What do you all feel about it?