This paper examines the social contract theories of Grotius, Hobbes, Pufendorf, and Locke, highlighting the failure of their contractarian defenses of the military and military service. In order to ground the duties of military service, each theorist presumes a chivalric gender order wherein men as men are expected to be willing to sacrifice themselves as violent instruments for the sake of their families and communities. While Grotius, Hobbes, and Pufendorf use the contract method to defend absolute, or near absolute, political authority wherein subject's primary political obligation is to serve the sovereign in war upon command, Locke uses the contract method to create a liberal political order that preserves the natural rights of subjects. Nevertheless, Locke maintains the commitment to self-sacrificial military service. In Locke, then, the military is peeled away from liberal civil society and we see the first statement of the civil-military distinction that persists today.