Mass Shootings debate thread: What public policy options should be pursued?

[Middle-aged Europe]

As far as I am concerned private gun ownership might just as well be banned altogether. At the same time, I'm realist enough to understand that this isn't and probably won't ever be possible within the context of America's political culture. So I'm open to any form of compromise that limits guns falling into the hands of crimnals, mentally unstable people, political or religious extremists (and I'm already hearing people crying about that you can't let the government decide who is an "extremist" and who is not - well, f**k them, that's not a point I'm willing to compromise on, the government is elected by and representing the people after all), and people who are generally untrained in handling guns.