NATO was created to prevent a major war in Europe, a task it accomplished well for many decades. Apart from the brief Kosovo war in 1999, its members never had to fight together or coordinate a joint response to aggression—until a year ago, when Russia invaded Ukraine. NATO’s response thus offers fresh, real-world evidence about how contemporary alliances work in practice.
The recent behavior of Russia and the West confirms that states form alliances not to balance against power but to balance against threats. The way NATO has done so has also revealed much about both the alliance’s virtues and its enduring pathologies. The war may have given NATO a new lease on life and shown the value of its well-established procedures, but it also underscores the degree to which its European members remain dangerously dependent on the United States.
As the world moves toward multipolarity, alliances will only matter more. In an age when no single country stands unchallenged atop the international system, success will depend on rival powers’ ability to form a coherent and capable grouping and exercise power collectively. Above all, the invasion of Ukraine and its aftermath show that leaders court disaster if they fail to understand why alliances form and how they work.
The concept of a balance of power—the idea that countries typically join forces to check powerful rivals—has been around for centuries, but in reality, countries more commonly seek allies in response to threats. Powerful states can be more threatening than weaker ones, of course, but where they are located and how their intentions are perceived can be equally important. Strong states are usually more worrisome to their immediate neighbors, especially when they appear willing to use force to change the status quo.
Read the full piece in Foreign Affairs.