The first reaction to the Aurora Massacre was the usual call for making sure that "this never happens again". Everyone from New York City Mayor Bloomberg to author Salman Rushdie to mystery writer Patricia Cornwell called for imposing gun control to insure "this never happens again".
And yet if we were to confiscate every privately owned firearm and outlaw the manufacture of new ones in the country, if we were to forcibly institutionalize anyone suspected of being mentally ill, and if we added naked scanners to movie theaters; we still could not insure that this will never happen again.