If they successfully persist in this, they do so in direct violation of the Constitution. They will no longer be one of "us" and should not expect to be treated as such. Instead, they will be seen by many as a domestic tyranny and conquering power - and justly so!
What they are purposely provoking by using the excuse of "mass murder" to take away one of our most bedrock rights is much more likely to end in genuine mass murder than fix that currently minute problem - and if it turns to violence it doesn't much matter which side "wins" in the end.
Civil wars are unbelievably ugly and and bloody. Nobody in their right mind should want one or provoke one. It is a horror that usually burns brightly and indiscriminately until either one side or the other wins and imposes their will on the vanquished by more violence - or until somebody stronger from the outside steps in to stop the carnage. In our case, that is unlikely to happen. However, there would be plenty of vultures circling high to swoop in and feast on the bloody pieces. In every instance, it ends in national and personal agonies with the worst extremes.
But, here these fiends are... encouraging it, courting it, for their own nefarious ends!
If they persist, this will not end well. Not at all. For anybody - except the vultures.