Sport provides a powerful metaphor and case study for one of the more constant identity conundrums throughout US history: whether to play with the rest of the world or remain apart from it. Even the term “American exceptionalism” has always been ambiguous: Does it mean #1 or the only one? In sport, America resolved its conundrum by inventing its own games, and then trying to get others to play them, with mixed results. Most notably, Americans created their own competing varietal of “football,” separate from the world’s default sport. But things have been changing in recent decades, and as next summer’s North American FIFA World Cup approaches, the two footballs appear to be converging; Americans are shedding their sports isolationism. How and why has this happened, and what implications does this have for how Americans engage with the world, on and off the field of play?