Even before its announced completion date of 2018, the European Phased Adaptive Approach (EPAA) to regional missile defense in Europe can declare victory. So far it has been implemented close to schedule and below budget despite continuing problems related to cost, debates about financial burden sharing, and Russia’s warnings about its threat, real or imagined, to European security and stability. Russian aggression in Crimea and Ukraine and its intervention in Syria have helped to shore up broad political support for the project. The sharp tension trajectory of Russian-NATO relations and the need to reassure Eastern European allies does however mean that Russia and a few domestic critics will continue to see EPAA as a political lever to stoke the fires of uncertainty about U.S. commitment and to play on the fears in Eastern Europe of abandonment in their first hours of need should a Russian attack occur. Expansion of the EPAA’s capabilities beyond the current projected capability of the system by 2018 will be difficult given the costs and the competing demands for missile defense assets elsewhere around the globe. Barring any significant ratcheting up of Russian threats and other security risks in Europe, significant expansion of the EPAA is unlikely, but so is any reduction in commitment to the project as it stands now. However, there are many assumptions and challenges still to be discussed and confronted if EPAA is to fulfill all of the political and military expectations set first by the George W. Bush administration and the revised version under the Obama administration. This essay will examine each of these challenges in turn, and gauge the seriousness of the dangers and risks, both political and military, involved. There is little present evidence that the EPAA is at risk of drastic changes to its planned deployment, either in favor of increased capability or a decreased U.S. commitment to fulfilling the promises already made. This is as it should be. The EPAA, to quote Brad Roberts, is not a “fool’s errand.”i What remains to be seen is how the United States and NATO will address the challenges, old and new, that face the EPAA and indeed all aspects of reliance on missile defense to deter and defend against growing threats.