After the sentencing of Boston Marathon bomber Dzhokhar Tsarnaev last week, I’m revisiting some thoughts from the days after the 2013 bombing:

Zebadiah Carter describes himself living in “an era when homicide kills more people than cancer and the favorite form of suicide is to take a rifle up some tower and keep shooting until the riot squad settles it.” In 1980, this remark by the main character in a Robert Heinlein novel sounded like the science fiction that it was. Now it echoes like a prophecy.

Random acts of mass violence in the United States still horrify us but no longer shock us. We’ve heard too many stories, seen too many pictures. And too many of them are depressingly the same:

• 20 students and 6 adults murdered at Sandy Hook Elementary School.
• 12 killed and 58 wounded at the Century Theater in Aurora, Colorado.
• 13 killed and 30 wounded at Fort Hood.