Government compels, restrains and takes. Thomas Jefferson understood that when he wrote that our liberties are inalienable and endowed by our Creator, and the only reason we have formed governments is to engage them to protect our liberties. We enacted the Constitution as the supreme law of the land to restrain the government. Yet somewhere along the way, government got the idea that it can more easily protect the freedom of us all from the abuses of a few by curtailing the freedom of us all. I know that sounds ridiculous, but that's where we are today.
The right to self-defense is a natural individual right that pre-exists the government. It cannot morally or constitutionally be taken away absent individual consent or due process.