The next NATO summit, set for July in Warsaw, is arguably one of the most important meetings of the alliance’s heads of state in the post-Cold War era. European security is at its worst since the end of the Cold War, while Europe finds itself facing a range of serious internal challenges, including continued slow economic growth, the influx of migrants and refugees and the rise of extremist parties. The United States, on the other hand, is distracted by its own poisoned domestic politics and must contend with security challenges in not only Europe, but also the Middle East and the South China Sea.

Still, NATO members have a chance at the summit to set the alliance on the right path forward, if the meeting can deliver a boost to defense and deterrence in Europe’s east, and begin to formulate a more active role for NATO around the Mediterranean. ...