There are surely more disruptions to come. Stephen E. Flynn, a security expert and former military officer who is co-director of the George J. Kostas Research Institute for Homeland Security at Northeastern University, ticks off the most likely threats: a breakdown in the power grid; interruption of global supply chains, including those that provide our food; an accident at one of the many chemical factories in urban areas; or damage to the dams, locks, and waterways that shuttle agricultural products and other goods out to sea. The No. 1 threat, he says, is a terrorist attack that prompts lawmakers and a frightened public to shred the Bill of Rights or overreact in another way.

The tendency in government has been to focus intensely on these threats—or other problems, considering the wars on cancer, poverty, drugs, crime, and so on—and to try to eliminate them.

“If you look at the post-World War II area,” Flynn says, “there is almost an overarching focus on reducing risk and bringing risk down to zero,” the idea that this could be done “if you brought enough science and enough resources and you applied enough muscle.” Since 9/11, that policy has meant spending vast sums to go after terrorists out there, but perhaps we aren’t safer.

“Why do we have all this money to go after man-made terrorist attacks, and then we let our bridges fall down?” Flynn wonders.

He advocates a different approach. We should make American society more robust so that it can absorb shocks and carry on. Part of that shift includes reorienting people’s attitudes so that they are more willing to deal with these uncertainties. The generation before World War II accepted risk as a matter of life, he says. “They had less ambition or hubris to believe that you would contain all of these things,” he says, “and a measure of character was how you would deal with adversity, how you overcame it.”