The multilateral arms control agreement that allows countries to fly unarmed surveillance aircraft over each other’s territory cannot afford to be torn up—but only a big transatlantic effort can save it.

Military substance has proven to be more important than fiery speeches and digital rhetoric. Let’s see if this NATO summit will prove it.

The proposed UN peacekeeping mission to Ukraine needs a combination of Western sticks and carrots. Diplomacy is not enough.

Moscow has made an extraordinary effort to undermine the coherence and unity of NATO. The alliance should respond with a series of measures to improve relations.