This book considered the moral/ethical implications of the US National Security Strategy policy of preemptive military actions. Using the just-war framework as a basis, this book examined both the policy and the specific military action in Iraq by considering the just cause, proportionality, and legitimate authority criteria. Based on this examination, the US policy and the actual intervention in Iraq violate both just-war theory and international customary law. However, the policy and military action are correct. The existing just-war theory and international law need to be updated to reflect the threats of the current world.