This thesis presents a critical analysis of international law on humanitarian intervention using Darfur, Sudan, as a case study. In the 20th century, international law was the perceived hurdle to humanitarian intervention. The international legal debate frames state sovereignty against humanitarian intervention. Within this legal framework, civilians are unprotected from atrocities that remain inside state territorial lines. States could conduct acts of genocide against their own population with impunity. After the intervention in Kosovo and the genocide in Rwanda, international law evolved to allow humanitarian intervention. The international legal debate shifted from state sovereignty against humanitarian intervention to a "Responsibility to Protect." The United States declared the atrocities in Darfur, Sudan, to be genocide in 2004. Four years later, there is still no protection of civilians and over 2 million displaced civilians remain in camps. Where the law has changed there is still a requirement for state interest. Until the genocide in Darfur is a vital state interest, the United States and other western countries will not intervene, regardless of what international law authorizes. If the only limitation on humanitarian intervention in Darfur is the perception that the genocide is not a United States vital interest, the U.S. military should be prepared for the view to change. With the creation of Africa Command, the U.S. military is beginning to view the continent of Africa with more interest. The U.S. military will be more effective if its leaders understand the evolution of the legal framework for humanitarian intervention, how to work within it, and the repercussions for working outside it when state interests change.