(Note for non-US readers: This will be another one of my America-centric posts. But don’t worry, it’s probably one you’ll agree with.)
There’s one argument in favor of gun control that’s always seemed to me to trump all others.
In your opinion, should private citizens should be allowed to own thermonuclear warheads together with state-of-the-art delivery systems? Does the Second Amendment give them the right to purchase ICBMs on the open market, maybe after a brief cooling-off period? No? Why not?
OK, whatever grounds you just gave, I’d give precisely the same grounds for saying that private citizens shouldn’t be allowed to own assault weapons, and that the Second Amendment shouldn’t be construed as giving them that right. (Personally, I’d ban all guns except for the bare minimum used for sport-shooting, and even that I’d regulate pretty tightly.)
Now, it might be replied that the above argument can be turned on its head: “Should private citizens be allowed to own pocket knives? Yes, they should? OK then, whatever grounds you gave for that, I’d give the precisely same grounds for saying that they should be allowed to own assault weapons.”
But crucially, I claim that’s a losing argument for the gun-rights crowd. For as soon as we’re anywhere on the slippery slope—that is, as soon as it’s conceded that the question hinges, not on absolute rights, but on an actual tradeoffs in actual empirical reality—then the facts make it blindingly obvious that letting possibly-deranged private citizens buy assault weapons is only marginally less crazy than letting them buy ICBMs.