For most of its existence, the Second Amendment was largely ignored by Constitutional scholars. Recently, a veritable cottage industry has developed in which two distinct camps have surfaced: so-called “Standard Modelers,” who argue that individuals have a right to bear arms for self-defense, the defense of the state, and, in the most extreme examples, to overthrow the government should it become tyrannical, and those who view the Second Amendment as a collective right vested in the state militias for the purposes of law enforcement, to protect against foreign aggression, to quell domestic insurrection, and as a check against federal overreach. Despite the enormous gulf between them, both sides agree that the right to bear arms provides a counterbalance against the federal government. This paper uses insights from game theory to shed new light on the adoption of the Second Amendment. The states suffered a commitment problem. They wished to cooperate with each other by founding a new republic, but feared the consequences of doing so: losing their freedom to a powerful government. The Second Amendment militated against the need for a large federal army, acted to counterbalance federal forces, and created the offensive means with which to confront a tyrannical government.