Right now, the United States and the larger international community is caught in a difficult debate over the use of drones against enemy combatants. Domestically, there is an odd confluence of views. The Obama administration’s policy on drones has been congenial to the conservatives, who oppose him on domestic issues; but his liberal allies, like the American Civil Liberties Union, are dismayed by what they perceive as his administration’s overuse of drones in Pakistan from 2004 to 2012. Has the United States pushed its drone attacks too far or not far enough? Have too many potential targets escaped attack because of an undue fear of excessive “incidental” or collateral damage to the lives and property of innocent non-combatants?

In this debate, the place to start is with libertarian thought, because it puts the use of force front and center. The root premise of libertarian theory is that no individual is allowed to use force or fraud, alone or in combination, to advance his personal interests over those of others—except in self-defense. The same basic rule is also a bedrock principle of international law. That one indispensable but pesky exception of self-defense complicates both domestic and international affairs. The domestic issues are hard; the international ones, almost impossible.

Self-Defense and Just War Theory

The jurist Hugo Grotius, in his 1625 masterpiece De iure belli ac pacis (On the law of war and peace), sought to apply a natural law approach to the problem of just war. Key to his inquiry is the need to reconcile the personal imperative of self-preservation with the due recognition of the like rights of other individuals, without which human society cannot survive.

Read more at Defining Ideas