ABSTRACT: US leadership in NATO has been declining since the Cold War ended. From a European perspective, the United States looks more and more like a reluctant ally. A re-nationalization of European security could occur without strong US leadership. The United States should, therefore, reassert itself in European security affairs--not with costly troop contributions, but by facilitating European unity and the development of relevant force structures. ********** Since its creation in 1949, NATO has been the most important alliance for America. US engagement and leadership in NATO has, however, been declining since the Cold War ended; this has been especially true during the Obama administration and in particular since the Libya War in 2011. In general, Obama's administration has engaged less in international security affairs; the strategic rebalancing to the Asia-Pacific has definitely moved the US focus from Europe to that region. (1) Although the US government plans to send more troops to Europe during 2017 and takes Russian aggression seriously, military operations against ISIS in Iraq and Syria have moved Washington's focus from Ukraine and Russia to the Middle East. In addition, the appetite for supporting Europe among US politicians and the American public seems to have declined. From a European perspective, the United States looks more and more like a reluctant ally, a characterization normally used by Washington to describe some of NATO's allies during the Cold War. (2) How does this reluctance manifest itself? What might it lead to? How should the United States act to facilitate more security in the transatlantic region without increasing the costs for American taxpayers? A re-nationalization or division of European defense and security is likely to occur without strong US leadership, and that will probably lead to a stronger Russian influence in European affairs which is clearly not in Washington's interest. The United States should, therefore, regain its leading role in European security affairs--not with massive troop contributions, as in the Cold War, but with strong and firm leadership that can facilitate European unity and help to create relevant force structures capable of defending Europe and contributing to its security. NATO's Declining Role in US Grand Strategy During the Cold War, Europe had a major role in US grand strategy and the United States led NATO with a firm hand. There was never any doubt the United States was the primus inter pares in European security affairs. To borrow Max Weber's concept, Washington led NATO in a charismatic way. (3) That has changed however. Even the Ukraine Crisis failed to make Europe a major player in US grand strategy. For example, in his comprehensive speech about the US foreign policy agenda for 2016 at the National Defense University (NDU) in January 2016, Secretary of State John Kerry, used just one sentence to describe the situation in Europe, and in that sentence he mentioned NATO once. (4) The demonstration of Europe's decreased importance in US security policy was not new. When Robert Gates gave his last major speech as Secretary of Defense he criticized NATO for being a two-tiered alliance, for having a dim, if not dismal future, and said future US political leaders may not consider the return on America's investment in NATO worth the cost. (5) Gates' view of NATO meetings was they were excruciatingly boring, and he had to do crossword puzzles to stay awake. (6) The Obama administration's decline in interest in Europe compared to other regions and the reluctance to lead NATO in traditional ways have been demonstrated over and over again, especially since the Libyan War in 2011. (7) That war caused a comprehensive discussion in the United States about burden-sharing in NATO between the United States and Europe, and especially who should take the lead in such an operation. …