The most popular response to mass shootings by NRA members is “Only a good guy with a gun can stop a bad guy with a gun.” Of course, the good guy with the gun has to have the same training and weaponry as the shooter and has to be fully prepared for the assault. In the real world, that doesn’t happen.
The second most popular response is “The bad guys will get guns anyway, so a prohibition will only take guns out of the hands of law-abiding citizens.” The next time you hear a politician say this, you should ask him if he thinks we should get rid of all of our drug laws, because, after all, the bad guys will always be able to get their hands on illegal drugs.
The fact is that most mass shooters buy their guns legally, and many of them would lack the knowledge and the fortitude to get them on the black market. An assault weapon ban would be a drop in the bucket in our overall American carnage, but even a drop in the bucket would help.
It won’t happen on a national level, of course, for the reasons I’ve described previously. State and local regulations in blue states are the best we can do.