The Atlantic: The Futility of Trying to Prevent More School Shootings in America. “As long as there is easy access to guns, there’s no way parents, teachers, and other specialists can thwart every violent teenager.”

“Details are only beginning to emerge about the gunman, and now it seems he kept his plans to himself, described in his personal journal. This would be unusual. In many of the other 21 (by CNN’s count) school shootings this year, there were clues to what would come to pass, to varying degrees. Typically, someone—a parent, a classmate, a teacher, a neighbor—had a hunch as to what would happen. Sometimes it was clear the child was mentally ill. Sometimes he had overtly displayed psychopathic traits. Sometimes other students steered clear of that particular boy at lunch in the hallway, because he was just plain scary. As Mary Ellen O’Toole, a retired FBI agent who’s an expert on school shootings, notes: “They never come out of the blue.“

If the clues were there, couldn’t these teens have been stopped? Faced with a dangerous child, families, schools, and police can do their utmost, and their utmost frequently staves off tragedy. But events like this point to a discomforting reality: Even though many potentially violent children can be treated and do get better, it’s impossible to ensure that every dangerous child will be reached. And, in the end, there’s not much that anyone can do to stop a determined shooter, aside from preventing him from getting a gun in the first place.”