This is the editor's letter in the current issue of The Week magazine.

When Nikolas Cruz decided to turn his former high school into a slaughterhouse, he went to the Sunrise Tactical Supply store in a Parkland strip mall, put down $1,000 in cash, and pointed to an AR-15. He could have chosen a different semiautomatic rifle, or a handgun, or a knife, but he wanted a weapon designed for war. It was the same choice made by the Las Vegas shooter (who shot more than 400 people in 10 minutes), the Sutherland Springs shooter, the Newtown shooter, and so many others. A civilian knockoff of a weapon designed for battlefields, AR-15–style rifles are the perfect tools for mass killings — easy even for a novice Rambo to fire accurately, with little recoil, and customizable with handgrips, sights, and magazines of 30 to 100 rounds. For 10 years, the federal government banned assault-style weapons and large-capacity magazines, but that law expired in 2004. Now the NRA and its allies fiercely oppose any renewal of the ban. Why?

You'll hear various disingenuous arguments, but in The​ Federalist​ this week, John Davidson provides the answer that is the bedrock of all gun-control opposition. The Second Amendment, Davidson says, was not meant to merely protect hunting and self-defense. No: "The right to bear arms stems from the right of revolution." Weapons designed for war must remain legal, Davidson says, so that Americans can "overthrow their government if it becomes tyrannical." It's a terrible shame, he concedes, that AR-15s have been used to shoot up schools, concerts, workplaces, and churches — but the Second Amendment "is worth dying for." Seen from this perspective, the bullet-riddled dead of Parkland, Newtown, Las Vegas, et al. are necessary sacrifices; their slaughter enables liberty-loving Americans to maintain the option of armed rebellion. This core belief, which drives the intractable opposition to any form of gun control, is not often publicly discussed; until it's addressed and confronted, the carnage will continue.