On the morning of the latest mass shooting, in a place that has become synonymous with tragedy, Tom Mauser’s phone started ringing at 5 a.m. When he turned on the news his first thought was “Oh God,” followed by an immediate: “Not again.”

“We’re not going to turn our country into one big fortress,” said James Alan Fox, a professor of criminology at Northeastern University and one of the nation’s foremost experts on mass murder. “People hate when I say this but it’s true: This kind of tragedy is one of the unfortunate prices we pay for our freedoms.”