What is always left out of this familiar scenario is an in-depth discussion of evil. Politicians and commentators almost never speak of evil as something that resides deep inside the human heart. All humans possess the capacity for evil. While it rarely rises to the level of mass murder, the capacity for doing great harm to other human beings lurks within each of us. This is what theologians mean when they speak of a "fallen" humanity.
Violent movies like "The Dark Knight Rises" do not make all people emulate the Colorado shooter, anymore than a movie about love causes people to love one another.
Would an armed guard at the theater have helped stem the carnage? No one can say. The guard might have been the first one shot. Some have suggested that at least one armed movie patron could have stopped the shooter. That also is difficult to say. In a darkened theater, a gunfight might have killed just as many, or more.
Sometimes there are no "solutions" that can forestall an evil act. Both President Obama and Mitt Romney set the right tone, asking for prayers for the victims and their families. Calling on that Higher Authority is the proper and perhaps only counterforce to this and other expressions of true evil.