As a Bostonian, I have complex feelings about my civil liberties and my family's personal safety in the aftermath of the Marathon bombings. My wife was a block from the first explosion. My son and four-year-old grandson had considered going to the finish line but then changed their plans. The dead and maimed could have been any of us. But I fear for my country on two opposite grounds. The emerging history of Dzohkahr Tsarnaev suggests that while the much-expanded national security establishment has been largely successful at thwarting organized assaults by terrorists, it cannot prevent a one-off attack by an extremist-influenced sociopath. To do so would require turning our country into a police state. How many more of us will have to be presumed enemies of the state in order for the rest of us to be safe from random bombers? After an attack like this, national security ratchets up, and never seems to ratchet back down.