The mass shooting at the Sikh temple seems even more horrifying than most. Of course victims are just as dead no matter what a killer's motive. But here the "best" case interpretation would be that the gunman was merely one more psychopath who decided to take out his madness by shooting into a mass of innocents -- like those in Aurora or Tucson, at Virginia Tech, and so on -- rather than someone attempting to launch flat-out racial or religious war.
Or, maybe it would be better if something about the case made it seem different enough, threatening enough, to allow America to do what other developed nations have done after their mass-shooting episodes. Many countries have endured them; but when that happens, most other countries have been shocked enough to change the conditions that make it so easy for deranged or bigoted people to kill a lot of people in a short time. Mass murders can happen in many ways -- with bombs, poison, even knives or cleavers -- but "assault weapons" designed to emit firepower at a high rate over a sustained period (from high-capacity magazines) enormously increase a killer's destructive potential. These weapons were of course banned under a measure the Clinton Administration fought to enact in 1994. It timed out in 2004, and they are legal again.