Private military firms are making a killing. They operate on all continents throughout the worldcommissioned by governments, intelligence agencies, private industries, warlords, drug cartels, and rebel groups to support their military and safety interests. Here in the U.S., as the massively expensive war in Iraq shows no signs of ending, our forces grow more and more dependent on the assistance of military contractors. Beyond Iraq, engagements of mercenary firms in foreign countries are multiplying, whether to protect oil investments in the Nigerian delta or for humanitarian reasons in...