On November 19, 2021, Kyle Rittenhouse was acquitted of homicide charges stemming from his killing of two people—Anthony Huber and Joseph Rosenbaum—at a protest of police violence in Kenosha, Wisconsin. Rittenhouse had armed himself and traveled to the protest, purportedly to defend Kenoshans’ property against looting. The acquittal sparked substantial public outrage about the state of gun laws and about the legitimacy of the criminal justice system more generally. In a similar case, Travis McMichael, Gregory McMichael, and William Bryan were charged with murdering Ahmaud Arbery in Brunswick, Georgia. There, the defendants believed that Arbery was engaged in criminal activity and pursued him with a gun. When Arbery took action to protect himself, Travis McMichael shot and killed him. Here too, many were concerned that an acquittal would lead to greater vigilantism. And while the jury ultimately convicted, Georgia law would have also allowed acquittal in a similar or even identical case. Such cases have raised public concern that certain states’ gun-use and self-defense laws effectively invite malicious individuals—including vigilantes and white supremacists—to kill with impunity.We argue that the situation is even worse than that. Certainly, premeditated intentional violence is of serious concern. However, under gun control regimes like Wisconsin’s and Georgia’s, even perfectly rational actors can easily find themselves committing deadly acts—no ill will required. Instead, when states combine generous open carry policies, lax assaultive threat rules, and weak (or nonexistent) duties to retreat, the laws themselves create the danger. Together, such rules generate incentives for ordinary, rational individuals to issue progressively escalating threats of deadly violence for the sake of their own protection. The result is a scaled-down version of the brinksmanship that characterized midcentury nuclear strategy: a small arms race.Here, we model the small arms race and suggest legal solutions. All practicable solutions involve breaking the cycle of escalation by imposing penalties on escalatory acts by one or more actors. Such penalties reduce actors’ access to self-defense in the short run while generating a less dangerous equilibrium for everyone in the long run. Because access to self defense is at the core of the Second Amendment, we explore the potential constitutional consequences of our findings. We argue that the Second Amendment, properly understood, must sometimes allow governments leeway to make self-defense harder. At a minimum, such interventions must be constitutional when the resulting equilibrium makes society, on net, significantly safer than the old one