Then again, each of the episodes described above were unique in their circumstances too. Today they may look like relatively modest deviations from an overarching story of Western solidarity. But that isn’t how they felt to the people living through them. In fact, during many of these crises, foreign-policy thinkers warned that the disagreements were the product of more than just an unfortunate misalignment of interests or an unlucky combination of leaders with conflicting worldviews. Rather, they insisted, there were structural, tectonic forces at play that threatened a common Western future.

And they often had a point. The Suez crisis, for instance, arose out of a longstanding trans-Atlantic fault line over European imperialism. The fight over the Iraq war a half-century later really did reflect the fact that, especially in the wake of 9/11, Americans and Europeans had different threat perceptions and attitudes about the use of military force.

In every case, though, the crisis receded, and habits of cooperation revived. The idea of the West proved capacious, flexible, and resilient enough to soldier on, despite the diversity and divisions within it.