This is the first use case for firearms I can understand. I hate it, I hate even that we have to have this discussion in a so-called civilized world, but here we are, and I understand it.
In a nutshell, the tension of existential leverage that the government has on you through their monopoly on violence is thereby "equally" leveraged by your right to own firearms - and the implicit extralegal right to use it against them - in an unjust event. And a government SHOULD be perpetually worried for when you'd eventually consider something "unjust" enough for you to exercise that right - as it creates a chilling effect for them to even attempt it.