As the nation sends it collective condolences to Boston, the city from which so much of America's history derives, we've noticed that, besides the grief and the anger, there is a sense that such random attacks are beyond our ability to prevent.
Sadly, this is true.
No matter how robust our security, no matter how vigilant our citizens or dedicated and skillful our law enforcement officials, a certain number of the terrorists who are bent on killing the innocent will find a way.
Yet as terrible as the Boston Marathon bombings were, another tragedy happened just two days later that was both more deadly, but also one we might have had some control over.
The explosion at the West Fertilizer Co. plant in West, Texas, killed at least 14 people.
Although officials haven't figured out what caused the explosion, there's no evidence that it was anything but an accident.
And accidents pose a far greater threat to us than terrorists do.
Every day dozens of Americans die in car accidents and home accidents and work accidents.
And with rare exceptions, each of those deaths could have been prevented.
If only the driver had buckled the seat belt, or slowed down when fog cloaked the street and obscured the pedestrian.
If only the worker had followed the safety procedures.
More than likely, when the investigation in Texas is finished we'll know precisely what could have been done to avoid that disaster, too.
None of this attenuates our anguish over lives needlessly lost, of course.
Whether those lives are lost because of another person's murderous intent, or because of innocent carelessness, the loss is equally permanent, and equally painful to the loved ones who survive.
Yet even now, when America remains numb after another terrorist attack that can seem almost the human equivalent of a lightning strike or a tornado, we should remember that we, as individuals and as a society, are far from powerless pawns.
To a large extent we control our own fates. Maybe we won't stop the next Boston. But we can prevent the next West, Texas.