What can we do about this? After the September 11 attacks, some of the wisest anti-terrorism counsel came from Bruce Schneier, profiled by Charles C. Mann in the September 2002 issue of The Atlantic. Schneier, a cryptographer and security engineer, stressed that the best countermeasures fail well. If your plan to stop skyjackings is to stop guns from getting through TSA checkpoints, then your plan sucks, because guns will eventually get through, and then what? If your plan is to get passengers used to the idea of fighting for their lives, that’s a good plan, because no matter what else happens, there will always be people on planes willing to tear hijackers apart like a pack of hyenas.

Senator Ted Cruz caught an enfilade of ridicule yesterday for suggesting that schools revisit their security by having only one door. The single point of entry could be monitored by an ace security squad, ready for all manner of threat. This demented proposal would fail very badly indeed, as soon as the guards nodded off, or were ambushed, or let a weapon slip by. Then the killer is in the school with his victims. Attempts to stop school shootings by confiscating the approximately 400 million guns in America fail the same macabre laugh test. Yes, it would be good to make guns harder to get, but it would be better, considering that we live in reality, to plan for the day (at the current rate, probably sometime next week) when a very bad person will get a gun and go berserk with it.