In recent decades the United States has forced a distinction between “private military contractors” and hired mercenaries that is both a legal fiction and more a work of art than law.
Global Warfare and Private Sector Armies
According to the 1989 United Nations Convention against the Recruitment, Use, Financing and Training of Mercenaries – a convention the United States has refused to sign – the use by states of private contractors for military purposes is a breach of international law.
Random Public Journal 