Bahahahahahahahahahahahahahahahaha you must be, literally, the only person in the world who thinks America's gun laws are not the issue!!!
Sure, you need to be a bit of a psycho to go and kill a whole bunch of people, but if you couldn't just go and buy a gun from any number of shops, then maybe you would not have done it.
The part in America's constitution that says they have the right to bare arms was an amendment, so fucking amend it again!!!
But so long as the NRA have so much power, nothing will ever change. Any president will struggle to change these laws, or even become president if he strongly disagrees with them.
So pull your head out of your arse.