When a federal court issues an order against enforcement of a government policy, the ruling traditionally applies only to the plaintiff in that case. Over the past several decades, however, some lower court federal judges have increasingly resorted to a procedural device—the “nationwide injunction”—to prevent the government from enforcing a policy against anyone in the country. Shrewd lawyers have learned to “shop” for a sympathetic judge willing to issue such an injunction. These days, virtually every significant congressional or presidential initiative is enjoined—often within hours—threatening our democratic system...