Gary Chapman, REGULAR CONTRIBUTOR 'Why aren't you in Iraq?" That's the question I posed recently to a group of undergraduates at the University of Texas, an honors class studying the legal aspects of the war on terrorism. I tried to ask this without antagonism or implicit criticism, but the question appeared to unsettle the students anyway. None of them had given military service much thought. All of them were against the war in Iraq. They told me they support the troops, but not the war itself. They won't sign up to fight a war they consider illegal and a mistake....