Are there Lessons to be Learned from Sandy Hook?

   It is said that those who won't learn from history are doomed to repeat it. So, if we were to do a little barnstorming, looking at Sandy Hook, and asking what we learned from it, what would we come up with?
   Can we look at the shooter, and the way things went down, and the protections we did or didn't have in place, and say, "This gives cause to change our society this way."?