America is undisputedly the greatest military power in the world. This will not change under President Donald Trump either. Yet America’s strength is only partially down to its statistical superiority and dominance in terms of military technology. Allies of the USA in Asia and Europe are equally important foundations for American security policy. But a gap is opening here. Donald Trump’s isolationism and “America first” nationalism threaten old alliances along with one of the foundations of global order. How should Europe deal with Trump’s security policy? Are we standing at a turning point for global world order?