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Historians generally portray the Great Wall as a military failture and a waste of resources. Spindler disagree, noting that the improved wall held back major attacks in the sixteeenth century. For the Ming, the wall was only part of a complex foreign policy, but because it's the most lasting physical relic, it reces disproportionate blame for their fall.

"People say, was it worth it?" Spindler said. "But I don't think that's how they thought at the time. You don't get a nation-state saying, "We're going to give up this terrain" or "We're going to sacrifice x number of citizens and soldiers" That's not a calculus they used. An empire is always going to try to protect itself."