I think Kevin McCullough hit the nail square on the head. We as a nation have abandoned the concept of evil as a force in the world. Why in the past few decades have events like this become relatively commonplace? A cop looks at means, motive, and opportunity to uncover the culprit in a crime. Applying this concept to this crime leads me to some very disturbing conclusions. If anything, the means and the opportunity have become more difficult since the 1960's. At that time access to weapons and to places where people gather was arguably easier, yet there were not attacks like this. We now have a myriad of gun laws and regulations. Sandy Hook was locked down already when the shooter showed up.