The war against ISIL is a critical US national security interest. It not only threatens to create a major center of terrorism and extremism in a critical part of the Middle East, and one that could spread to threaten the flow of energy exports and the global economy, but could become a major center of international terrorism. It is important to understand, however, that ISIL is only one cause of instability in the region, and only one of the threats caused by spreading sectarian and ethnic violence. Iraq is a key case in point. No defeat of ISIL can bring Iraq security or stability, or give it the unity and independent strength to resist pressure from Iran and threats based in Syria and Turkey. No military course of action can—by itself – create a stable regime and economy, and reduce tension between Iraqi Sunnis and Shiites, and Arabs and Kurds, to workable levels. Like Syria, Libya, and Yemen, military action must be joined to political and economic action and the creation of some form of viable governance.