A familiar horror strikes again in Santa Clarita

There's a cadence to the aftermath of school shootings.

Everyone plays their role, including journalists both near and far from the scene.

When news from Santa Clarita, Calif., began breaking, and #schoolshooting started trending on Twitter, it was rote to set aside the work that had consumed the first hours of my day: studies of the U.S-Mexico border.

Reflexively, I began a perverse calculation that in itself was a striking admission of how routine thinking can become