NATO, the largest and most powerful military alliance in history, turned seventy-five in April. In July, the leaders of NATO will return to the city where its founding document, the Washington Treaty, was signed in 1949. Most people have heard of NATO. Fewer know its most important document is the Strategic Concept, which is updated every decade or so, and sets the Alliance’s strategy. An even smaller group know about NATO’s “Concept for Deterrence and Defence of the Euro-Atlantic Area.”
The DDA—or the “Deter and Defend” strategy, as it is known in alliance circles—is the centerpiece of NATO’s dramatic “back to the future” transformation in recent years. The DDA has helped the Alliance be more forward-leaning in its defense and deterrence missions. For example, before Russia’s full-scale invasion of Ukraine in 2022, several DDA measures were implemented to counter Russian attempts to destabilize Ukraine and undermine Allied cohesion.
Since 2022, the DDA has been the linchpin in NATO’s efforts to deter Vladimir Putin from expanding his war of aggression beyond Ukraine. As NATO’s website explains, “The DDA Concept provides a single, coherent framework for NATO Allies to contest, deter and defend against the Alliance’s main threats.”