Theocentric natural law and just war doctrine ; --Anthropocentric natural law and its implications for international relations and armed conflict ; -- Rejection of natural law and its implications for international relations and armed conflict / Howard M. Hensel -- Preemption and preventive war / Gregory A. Raymond and Charles W. Kegley, Jr. -- Development of international humanitarian law and the continued relevance of custom / Jean-Marie Henckaerts -- Martens clause and military necessity / Mika Nishimura Hayashi -- Principle of distinction : beyond an obligation of customary international humanitarian law / Jean-François Quéguiner -- Principle of proportionality / A. P. V. Rogers -- Hors de combat : post-September 11 challenges to the rules / Avril McDonald -- Occupation responsibilities and constraints / Charles Garraway.