Mass shootings have become an American ritual. Someone murders a dozen or more people — schoolchildren in Connecticut, nightclub revelers in Florida, or concertgoers in Nevada. Shocked and horrified liberals shake their fists at the gun lobby and politicians too cowardly to stand up to their paymasters at the National Rifle Association (NRA). But nothing happens, and the activists roll over and go back to sleep. Then another mass shooting takes place, and the cycle begins again.

Gun control politics are immobilized because of an immovable constitutional barrier known as the Second Amendment. The forty-year drama around its interpretation does much to explain why popular support for regulation has failed to produce meaningful change.

For decades, liberal politicians equated the Second Amendment’s right to bear arms with the Third Amendment’s ban on the peacetime quartering of soldiers in private homes: both were harmless relics of a bygone era that did not infringe on the rest of the constitution. All Americans had to do was correctly understand the document — which, since all the best constitutional scholars were solid liberals, should not have been a problem. What could go wrong?