This terrorism in Moscow is horrible and a reminder that if people are willing to get caught/killed/die in the course of blowing up lots of people they are going to do it. Absent identifiable organizations dedicated to terrorism in our country, I'd guess the amount of law enforcement resources that can be usefully applied to stopping such events is pretty close to zero. I remember during the exciting post-9/11 days we'd regularly hear new warnings about possible targets. Shopping malls! And, well, duh, any places were crowds accumulate are possible targets and there isn't much we can do about it.
I was in SoCal post 9-11 and for some reason the powers that be were greatly concerned about car bombs at the airport. Car bombs. At the airport. Why? I have no idea. What makes airports special are...airplanes. Otherwise they might as well be a big shopping mall. Nor did I have any idea why the solution - only cabs and buses were allowed at the airport terminals, no private vehicles - would solve this (hint: not hard to obtain a cab). Anyway, I'm meandering a bit here, just making the point that if people want to blow stuff up they're going to and there isn't much we can do about it.
