Resilience is partly a matter of character, but it is also one of policy. Stephen Flynn, a scholar at Northeastern University who has written widely about this, argues that, despite the billions spent, we have never made it a priority. George W. Bush often explained, “We fight the terrorists overseas so that we don’t have to fight them here at home.” And indeed, the focus of policy in the Bush years was the fight abroad. At home we have spent hundreds of billions of dollars on a Department of Homeland Security that many experts agree is a disaster and should probably never have been created. And while al-Qaeda has diminished in strength, certainly in its ability to launch major attacks on military or symbolic targets, we remain unprepared for the most likely attacks, which are of the kind we saw in Boston.

In written testimony given last July to the Senate Committee on Homeland Security and Governmental Affairs, Flynn predicted that “small attacks carried out by one to three operatives, particularly if they reside in the United States, can be carried out with little planning and on relatively short notice. As such, they are unlikely to attract the attention of the national intelligence community and the attacks, once underway, are almost impossible for the federal law enforcement community to stop.”