David French goes there.
...The argument is not that a collection of random citizens should be able to go head-to-head with the Third Cavalry Regiment. That’s absurd. Nor is the argument that citizens should possess weapons “in common use” in the military. Rather, for the Second Amendment to remain a meaningful check on state power, citizens must be able to possess the kinds and categories of weapons that can at least deter state overreach, that would make true authoritarianism too costly to attempt.
As Justice Scalia ably articulated in Heller, the Second Amendment was designed to protect what Blackstone called “the natural right of resistance and self-preservation.” Without access to the weapons in common use in our time, the law-abiding citizen will grow increasingly — and intolerably — vulnerable to the lawless. Thus, to properly defend life and liberty, access to assault weapons and high-capacity magazines isn’t a luxury; it’s a necessity.
As to "the lawless," I can spell a few names for you: Hillary Clinton, Barack Hussein Obama, James Comey, John Chisholm, Lois Lerner, Francis Schmitz.....
Shall I go on?