The Bush regime invented 'illegal combatants.' (And it is actually unlawful combatant.)
The phrase "unlawful combatant" does not appear in the Third Geneva Convention (GCIII).<3> However, Article 4 of GCIII does describe categories under which a person may be entitled to POW status; and there are other international treaties which deny lawful combatant status for mercenaries and children. In the United States, the Military Commissions Act of 2006 codified the legal definition of this term, and invested the U.S. President with broad discretion to determine whether a person may be designated an unlawful enemy combatant. The assumption that such a category as unlawful combatant exists is not contradicted by the findings by the International Criminal Tribunal for the Former Yugoslavia in the Celebici Judgment. The judgement quoted the 1958 ICRC commentary on the Fourth Geneva Convention: Every person in enemy hands must be either a prisoner of war and, as such, be covered by the Third Convention; or a civilian covered by the Fourth Convention. Furthermore, "There is no intermediate status; nobody in enemy hands can be outside the law."<4> However—unlike the terms "combatant", "prisoner of war", and "civilian"—the term "unlawful combatant", or similar, is not mentioned in either the Hague or the Geneva Conventions. So while the former terms are well understood and clear under international law, the term "unlawful combatant" is not.<5><2>
At the First Hague Conference, which opened on 6 May 1899, there was a disagreement between the Great Powers—which considered francs-tireurs to be unlawful combatants subject to execution on capture—and a group of small countries headed by Belgium—which opposed the very principle of the rights and duties of armies of occupation, and demanded an unlimited right of resistance for the population of occupied territories. As a compromise, the Russian delegate, F. F. Martens, proposed the Martens Clause, which is included in the preamble to the 1899 Hague Convention II – Laws and Customs of War on Land. Similar wording has been incorporated into many subsequent treaties that cover extensions to humanitarian law.<6><7><8>
http://en.wikipedia.org/wiki/Unlawful_combatantThe huge leap to 'anyone bearing arms against us in Afghanistan' not being covered by the GC, the implication of your first post. Is unsustained by any legal doctrine other than the crap issued from the Bush regime and the complaint Congress of the last seven years.