We are shocked and saddened by the massacre in Aurora, Colo. But Aurora is part of a pattern, not an isolated incident. Two days earlier, 17 were hurt outside a bar in Tuscaloosa, Ala., when a gunman opened fire.

There is no safe zone.

Rep. Gabrielle Giffords and 18 others were shot in a Tucson, Ariz., shopping center. Virginia Tech students were mowed down on campus. In Chicago, 228 people have already lost their lives to gun violence as of mid-June. Nationwide, there have been 60 mass shootings since the Tucson horror, according to the Brady Campaign. Every year, about 100,000 Americans are victims of gun violence, with about 30,000 killed. Aurora is shocking — but the shock has become routine.

We fixate on the details of the killer. James Holmes was an honor student who ran into trouble, dropped out of school, apparently suffered depression. He saw himself as the Joker, the villain without a cause, eager only to sow violence and disruption for its own sake. Dressed in black body armor, he walked into the movie theater playing the new Batman movie carrying two handguns, a shotgun and an assault rifle. There was no defense when he opened fire.

Our leaders offer condolences and prayers, as President Obama and Republican presidential candidate Mitt Romney did immediately. But we need both prayer and policy to provide for domestic tranquility. Depression isn’t isolated. Mass depression and mass access to guns is a recipe for massacre. We must do more than mourn. We must act to limit domestic terrorism.

Holmes purchased the four guns he carried in local Colorado gun shops along with 6,000 rounds of ammunition in the last 60 days. How could he arm himself with an assault rifle that is useful only to hunt humans? It was easy because in Colorado, it was perfectly legal. According to the Brady Campaign, this is the current state of gun laws in Colorado: