A Lawsuit Targeting Gun Makers Would Hit Us All

Can the flutter of a butterfly’s wing cause a hurricane half a world away? Can stepping on a butterfly change the course of history, as imagined in Ray Bradbury’s “A Sound of Thunder”? Imponderables like this have long fascinated philosophers and science-fiction writers. But if a case currently before the Supreme Court goes the wrong way, such flights of fancy will be injected into our law, vastly expanding the scope of potential liability for every individual and business in the country.

Until recently, no one expected butterfly-effect theories to invade our legal system. The age-old doctrine of “proximate cause” ensured that parties can be held liable only for harms that are the direct and immediate consequence of their own actions. They can’t be held responsible for harms connected with their own actions in only a highly attenuated way. And rightly so—the alternative would be a nightmare world in which everyone is at risk of being held liable for consequences occurring downstream of their actions, no matter how remote. As Justice Antonin Scalia memorably put it, “ ‘for want of a nail, a kingdom was lost’ is a commentary on fate, not the statement of a major cause of action against a blacksmith.”