The purpose of the Second Amendment's protection of the right to keep and bear arms is to give citizens the power to deter tyrants from inflicting great harm.
It protects the individual's right, when necessary, to shoot tyrants. And it protects the right to shoot at them with some of the same weapons they would use upon us. It's not that tyrants need be killed; but confronting weapons can be persuasive in reducing aggression. Can you imagine the same Holocaust if Jews had had the right to keep and bear arms?
Indeed, if Europeans and other citizens had had the right to keep and bear arms and widely exercised it, most of the violence there in the 20th century could have been avoided.
Another crucial point: If the Holocaust had not occurred, even fools would not have welcomed armed, foreign Jews invading and taking over vulnerable Palestine. Without such tyrants, and England's tolerance of them, the Middle East could now be an oasis of peace, rather than a powder keg to ignite World War III.
Just as humanity must be defended from tyrants, we must also prevent our neighbors from inflicting great harm upon innocents. True patriotism requires bold dissent when acts of aggression and war are ordered, with the vast, unwinnable costs that violence imposes.
Evil are those who commit the carnage and blindly wave the flag against peace and justice. Tyrants, both foreign and home-grown, reject the universal rule for permissible human conduct: "Anything that's peaceful."