It's interesting (in a horrified and disgusted sense of the word) to see the US reactions to their latest mass shooting.
Is it to think logically about the single common thread between mass shootings (which is to say, GUNS) and work to eliminate them?
No.
It's to try and develop ways so that when the next mass-shooting occurs you can minimise the number of people killed.
This is explained in two ways: either arming everyone or enabling people a better chance to hide.
As I noted on my post on the ten years since Port Arthur
here we have discovered (and proven) a direct link between freely available guns and mass shootings.
Removing the availability of guns from the population doesn't necessarily reduce gun crime, but it will prevent you from being gunned down by some lunatic.