The April 2015 sentencing in the DC federal district court of four former Blackwater Worldwide security guards to lengthy jail terms for killing 14 civilians in a Baghdad, Iraq traffic circle in 2007 stands as an illustration of the myriad legal and policy issues associated with the use of contractors on the battlefield. Hired to provide security protection to State Department personnel, all the defendants believed that they acted in self-defense and will most certainly appeal (one received life in prison and the other three 30 years each). The case was tried in federal court because unlike military personnel, civilian contractors accompanying the armed forces in the field do not fit neatly into well-defined arenas of military law and procedure. While the military has always carefully outlined its own command structure for its uniformed personnel, the picture is far less certain for civilians accompanying the forces. In fact, prior to the John Warner National Defense Authorization Act for Fiscal Year 2007, which now authorizes trial by military courts-martial for crimes committed by civilian contractors who accompany military forces in both declared wars by Congress and on contingency operations, the Court of Military Appeals in U.S. v. Averette (1970) had made it clear that except in a Congressional declaration of war (which last occurred in 1941 during World War II), civilian contractors were not subject to the provisions of the Uniform Code of Military Justice (UCMJ), that is, military law.
There are three primary statutory avenues by which civilian contractors could be subject to criminal liability, the Special Maritime and Territorial Jurisdiction of the United States (SMTJ), the Military Extraterritorial Jurisdiction Act (MEJA), and the UCMJ. The USA PATRIOT Act amended the SMTJ and allowed for jurisdiction for offenses committed by or against a U.S. citizen or national, or on a facility used for U.S. foreign missions, or operations to include a location outside the jurisdiction of any nation (like Somalia).
MEJA authority rests with the Attorney General via the respective federal districts and provides jurisdiction for crimes committed by civilian employees and contractors of the DOD operating with or near the U.S. military outside of U.S. territory, for felonies (offenses punishable by more than one year imprisonment).