The elder brother was clearly influenced by an apocalyptic strand of Islam that Al Qaeda heavily referenced. But the younger brother hasn't been shown to have the same affiliations. The family - at least the father - is still in Russia. Dzhokhar appears to be a very intelligent boy (and he's a boy) who's had success here in the United States. Tamerlan - the elder brother - was clearly more alienated and isolated.
So far five people are dead, including Tamerlan. I hope that number stays at that level. (The number in West, Texas will be a multiple of five, sadly.)
The Clinton Administration was derided by the Bush Administration for treating terrorism as a law enforcement issue. But if we are moving to a new normal of various forms of terrorist attacks - from Jared Loughner-type mentally ill people to lone wolves like Tamerlan Tsarnaev - we need to steel ourselves to the fact that acts of mass violence are not done with.
And they will never be done with.
And we have to respond to them quickly, forcefully but with perspective. Adam Lanza killed 27 people, including his mother. We can't pass background checks. But I fear what may come from a nation periodically traumatized by events like Boston.
This is what I mean by the Israelification of terror in the US. Israelis live in a constant state of vigilance, but they also live free and normal lives. We have to get over the bedwetting fear that encompasses many quarters of our body politics if we are going to survive this era in our history.
Almost all types of violent crime are dropping, except for these mass events. And the very nature of these mass events - their randomness, their awfulness - make them more indelible.
And we can't let that happen. In his remarks yesterday, President Obama was right. We can't given in to fear. We have to run the marathon again next year and the year after that. Well, not me personally; I'm too fat and my feet are shot.
But the motives of these two young men, one barely more than a boy, will be hugely important in making sure that we react to this crime, not overreact.
UPDATE: I'm not going to try and keep up with this, but this report (half way down the post) about the older brother being a "loser who deserved to die" (and this was his uncle) gibes with my thinking that this alienated, sociopath older brother got his younger brother mixed up in all this.