The events reveal, dramatically, the foolishness of the project of "missile defense." As has been obvious all along, and pointed out repeatedly by strategic analysts, if anyone wants to cause immense damage in the US, including weapons of mass destruction, they are highly unlikely to launch a missile attack, thus guaranteeing their immediate destruction. There are innumerable easier ways that are basically unstoppable. But today's events will, very likely, be exploited to increase the pressure to develop these systems and put them into place. "Defense" is a thin cover for plans for militarization of space, and with good PR, even the flimsiest arguments will carry some weight among a frightened public.
In short, the crime is a gift to the hard jingoist right, those who hope to use force to control their domains. That is even putting aside the likely US actions, and what they will trigger -- possibly more attacks like this one, or worse. The prospects ahead are even more ominous than they appeared to be before the latest atrocities.
As to how to react, we have a choice. We can express justified horror; we can seek to understand what may have led to the crimes, which means making an effort to enter the minds of the likely perpetrators. If we choose the latter course, we can do no better, I think, than to listen to the words of Robert Fisk, whose direct knowledge and insight into affairs of the region is unmatched after many years of distinguished reporting. Describing "The wickedness and awesome cruelty of a crushed and humiliated people," he writes that "this is not the war of democracy versus terror that the world will be asked to believe in the coming days. It is also about American missiles smashing into Palestinian homes and US helicopters firing missiles into a Lebanese ambulance in 1996 and American shells crashing into a village called Qana and about a Lebanese militia - paid and uniformed by America's Israeli ally - hacking and raping and murdering their way through refugee camps." And much more. Again, we have a choice: we may try to understand, or refuse to do so, contributing to the likelihood that much worse lies ahead.