NATO moves toward its next summit (to be held in Newport, Wales in September 2014) in a mood of anxiety and uncertainty. This is not simply because telling questions are being asked of the alliance in relation to Afghanistan and Ukraine, but because the twin motors which have sustained NATO now show signs of considerable wear and tear. The first of these motors relates to principles of purpose. This encompasses the activities (or purposes) which NATO has consciously pursued in the last 25 years: namely, operations, enlargement, partnership, transatlanticism and security. The second is principles of function: the means, in other words, by which NATO is kept in motion. Here, American leadership, cohesion and trust, burden-sharing and credibility all matter. These motors are not about to completely break down (NATO has underlying strengths which make that unlikely) but they do need attention. NATO's good health requires it to focus on a series of core tasks—what this article refers to as readiness, reassurance and renewal. These three tasks speak to an agenda of consolidation and preservation, rather than one of task expansion. But this is not a conservative agenda; grasping the nettle of prioritization and focus requires, in itself, a certain foresight and enterprise. Managed successfully, it is an agenda that will preserve and strengthen NATO in what are increasingly troubled times.