The changing nature of war affects the law of armed conflict, at the same time as national security has now developed an internal as well as external aspect. Traditional wars between nation states are no longer the rule. The non-state actor as threat has gained credence (popularly, terrorism and its claimed breeding ground in failed states), linked in practice to issues of intervention on the territory of states harboring such groups. In military circles the idea of armed struggle between modern military forces and what were formerly called guerillas has now largely been replaced by the terminology of asymmetric warfare and the concept of intelligence and preventive action interchangeably within U.S. borders and overseas.

These are the changing circumstances against which the legal issues now unfold. Beyond questions about legal justifications for the use of armed force (jus ad bellum), armed conflict law as part of public international law contemplates rules for the lawful conduct of military operations largely designed to protect non-combatants. This is jus in bello, which governs also lawful treatment of combatants or soldiers, bearing in mind that they are not often uniformed state military forces under current conditions. Jus in bello issues can be reduced at a certain technical level to the question whether standards largely developed since 1900 under treaty for soldiers in international wars have been carried over via customary law to internal armed conflicts involving non-traditional combatants, and what are those supposed unitary standards? Opposing views contemplate that different and presumably lower legal standards may apply in internal armed conflicts. Such legal issues are visible under current circumstances of asymmetric warfare in conjunction with questions about military prisoner status and detentions, including the permissible bounds of interrogation versus torture following the Abu Ghraib prison scandal in Iraq but also the treatment at the Guantanamo Bay facility of alleged Al Q’aeda captives from Afghanistan.

Going back to 2004, the Supreme Court recognized authority in the Judicial Branch to review national security detentions by rejecting broad claims of largely unreviewable Executive Authority. However, permissible substantive constitutional standards for detentions and interrogations grounded solely in Executive Authority remain unclear. At the same time, it seems likely some statutory basis for national security detentions and interrogations will accompany or closely follow renewal or amendment of the U.S. Patriot Act required by year’s end due to the law’s sunset provisions. Once that happens, the debate presumably will revisit individual liberties issues under the rubric of internal security in the form of the question what substantive constitutional standards are applicable to internal security detentions and interrogations with a statutory basis but outside the scope of ordinary law enforcement measures? Meanwhile, perceived internal threats with overseas connections arguably gravitate against the strict separation of domestic and foreign intelligence collection under legal structures prevailing since the 1970s.