That period culminated in an international conference in Geneva in 1977, which famously established new treaties reflecting and updating the rules of warfare. The end result was a pact agreeing to a worldwide prohibition on “superfluous injury or unnecessary suffering,” words that again mirrored Pictet’s maxim. And words that are now included in war manuals of the U.S. military.

The foundation of the White House’s position is, in the end, based on a historical relic. Nonetheless, this view has been accepted as mainstream in the United States: Even strong critics of the drone program have begun to mouth it. For example, a recent critique of the Justice Department’s legal analysis accepts as a truism that “unless he surrenders, a combatant can be killed regardless of activity.”

The disjuncture between the American conversation and the modern laws of wars even shows up in a recent discussion with the American political philosopher Michael Walzer. He indicated his strong support for the White House position, and stated that in “asymmetric warfare, without a front, without soldiers in uniforms, targeted killing seems a necessary form of warfare — and justified if we get the targets right. Why does risk to U.S. forces make a difference?”

Compare this, however to the High Court of Israel’s landmark judgment in 2005 on targeted killings. In a ruling that captures modern developments of international law, the Israeli judges stated that lethal forced must be abandoned when “a less harmful means can be employed.” They explained that a key factor is whether such restraint involves “a risk so great to the lives of the Israeli soldiers.”

A careful reading of law and modern history shows how wrong the White House position is. In law school, we teach that getting the law wrong can be as bad as ignoring it altogether. In this case, at least we still have a chance to get the law right.

Goodman is a law professor at New York University and the author of the forthcoming article “The Power to Kill or Capture Enemy Combatants,” in the European Journal of International Law. Follow him at rgoodlaw.