How much military force does a global superpower require? Answering this question has challenged U.S. leaders and defense planners for more than 20 years. In the immediate aftermath of the first Gulf War, U.S. leaders decided to use the requirement to conduct two major regional conventional contingencies (MRCs) at the same time as the basis for sizing the U.S. military. Every subsequent review of U.S. defense policy and programs has reaffirmed the two-war standard. In fact, every Administration for the past two decades found that a force sized to fight two wars was essential for meeting the ongoing demands for forward presence, crisis response, regional deterrence, humanitarian assistance, building partnership capacity, homeland defense, and support to civil authorities.