The issue is not mental health. The issue is not violent video games. The issue is not a culture of death. The issue is not the breakup of the family. The issue is not black trench coats or goths or Marilyn Mason or whatever straw man that irresponsible people want to make up to defend their irresponsible behavior.
The issue is that we freely hand out weapons designed for mass murder and then hope nobody will mass murder with them.
Beauty is Imperfection 
Yes, that is the issue, but it can only be changed by act of LAW. That can be done, but NOT if you try to get politicians to do it. They won’t. Elected pols do turnabouts every day, have no sustained focus. Forget the president or congress. You need LOCAL leadership, in every state, with vote power to demand change. The Grover Norquist method.
You can get a constitutional amendment that way, but the odds against it are great. Both women’s suffrage and prohibition took decades, and there was nothing in the constitution – like a second amendment – to stand in the way.