A few thoughts on Boston. Because of 9/11, we now have a mental map that orients us in terror. The images of smoke rising over a great American city; the raw video with the “Oh my God, oh my, God” soundtrack; a particular detail of the tragedy that brings us to our knees, in this case a father who was heading to triumph over the finish line only to be greeted by a dead son, a maimed daughter and wife; a resolute president. Maybe the mental map does us some good, gives us some reference. Perhaps it helped the many people who stayed with or ran to the mayhem to see if they could help; they had seen others do the same on 9/11. The mental map may also help us in that delicate balance between grief and revenge, and in restoring our equilibrium. We are tougher now; we know more of what to expect.

We have been smart and lucky, I guess, that attacks on U.S. soil have been so rare. How many times have we thought about how easy it wold be to detonate an unsophisticated bomb in a subway, a shopping mall or a sporting event? Yet, it is still rare. Do we have fewer enemies than we think? Are we better at stopping them?

Final thought: These attacks occurred at a time of rare bipartisan progress in Washington on gun safety, immigration and maybe even the budget. One thing that terror does is strip us, temporarily, of our silliness and make us a more serious country. There can be comfort in that, too.