IMO, the definition of "unlawful combatant" from Quirin is in these passages, with underlining showing the relevant points:
By a long course of practical administrative construction by its military authorities, our Government has likewise recognized that those who during time of war pass surreptitiously from enemy territory into our own, discarding their uniforms upon entry, for the commission of hostile acts involving destruction of life or property, have the status of unlawful combatantsSpecification 1 states that petitioners 'being enemies of the United States and acting for ... the German Reich, a belligerent enemy nation, secretly and covertly passed, in civilian dress, contrary to the law of war, through the military and naval lines and defenses of the United States ... and went behind such lines, contrary to the law of war, in civilian dress ... for the purpose of committing ... hostile acts, and, in particular, to destroy certain war industries, war utilities and war materials within the United States'.
"The spy who secretly and without uniform passes the military lines of a belligerent in time of war, seeking to gather military information and communicate it to the enemy, or an enemy combatant who without uniform comes secretly through the lines for the purpose of waging war by destruction of life and property, are familiar examples of belligerents who are generally deemed not to be entitled to the status of prisoners of war, but to be offenders against the law of war, subject to trial and punishment by military tribunals."
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I believe this provides the basis for AG Ashcroft's position.
Also, OBL declared war on USA several years ago. The fact our miscreant President Klinton did nothing is a reflection on HIM. Not USA. We had the right to respond then, and certainly after 9-11 do likewise. Massively I would hope...