That's not entirely true though, at least (living here) it doesn't seem that way. It seems that barely a week goes by without some rando running amok with another shooting in a local mall or in a school somewhere in the state and these people are then deemed "mentally ill" and nothing happens to stop it happening again.

There sure must be a lot of mentally ill people in the USA...

As for the last point, the US does not have military bases overseas for any reason other than self-interest. It is a lot easier to project power around the world when you have a permanent base in the nearby neighbourhood - there is no altruism involved. The US chooses to do that, and makes arrangements with foreign governments, and should indeed bear that cost, although if you could possibly prevent your WAGs from driving on the wrong side of the road, killing the locals, and fleeing the country in future, we'd appreciate that.

And one last point I'd make is that I don't believe that it matters whether it's suicide, or gang-based, or black-on-black, or "mentally ill", or any other way in which Americans slice and dice the statistics to try and make them more palatable. It's still dead people. And that is truly awful.