In vast swathes of America, the sacredness of the Second Amendment has become a political third rail, never to be questioned. Gun rights supporters wear tri-cornered hats, wave the stars and stripes, and ask what would have happened if the revolutionaries had been unarmed when the British were coming. They have had great success in conflating unfettered gun ownership with the Founding Fathers, the Constitution, and all things American, even in an era of repeated mass shootings. Yet the all-too-familiar narrative of America's gun past, echoed in the Supreme Court's Heller gun rights decision,...