Seeking such authorization would help draw the debate over continued drone strikes out of the shadows. Paradoxically, as the war on terror winds down, and as the number of drone strikes falls, the controversy over them may rise.

V. Come Out With Your Hands Up!

Once the pursuit of al-Qaeda is defined as “law enforcement,” ground assaults may be the only acceptable tactic under international law. A criminal must be given the opportunity to surrender, and if he refuses, efforts must be made to arrest him. Mary Ellen O’Connell believes the Abbottabad raid was an example of how things should work.

“It came as close to what we are permitted to do under international law as you can get,” she said. “John Brennan came out right after the killing and said the seals were under orders to attempt to capture bin Laden, and if he resisted or if their own lives were endangered, then they could use the force that was necessary. They did not use a drone. They did not drop a bomb. They did not fire a missile.”

Force in such operations is justified only if the suspect resists arrest—and even then, his escape is preferable to harming innocent bystanders. These are the rules that govern police, as opposed to warriors. Yet the enemies we face will not change if the war on terror ends. The worst of them—the ones we most need to stop—are determined suicidal killers and hardened fighters. Since there is no such thing as global police, any force employed would likely still come from, in most cases, American special-ops units. They are very good at what they do—but under law-enforcement rules, a lot more people, both soldiers and civilians, are likely to be killed.

It would be wise to consider how bloody such operations can be. When Obama chose the riskiest available option for getting bin Laden in Abbottabad—a special-ops raid—he did so not out of a desire to conform to international law but because that option allowed the possibility of taking bin Laden alive and, probably more important, because if bin Laden was killed in a ground assault, his death could be proved. The raid went well. But what if the seal raiding party had tripped Pakistan’s air defenses, or if it had been confronted by police or army units on the ground? American troops and planes stood ready in Afghanistan to respond if that happened. Such a clash would likely have killed many Pakistanis and Americans, and left the countries at loggerheads, if not literally at war.

There’s another example of a law-enforcement-style raid that conforms to the model that O’Connell and other drone critics prefer: the October 1993 Delta Force raid in Mogadishu, which I wrote about in the book Black Hawk Down. The objective, which was achieved, was to swoop in and arrest Omar Salad and Mohamed Hassan Awale, two top lieutenants of the outlaw clan leader Mohammed Farrah Aidid. As the arrests were being made, the raiding party of Delta Force operators and U.S. Army rangers came under heavy fire from local supporters of the clan leader. Two Black Hawk helicopters were shot down and crashed into the city. We were not officially at war with Somalia, but the ensuing firefight left 18 Americans dead and killed an estimated 500 to 1,000 Somalis—a number comparable to the total civilian deaths from all drone strikes in Pakistan from 2004 through the first half of 2013, according to the Bureau of Investigative Journalists’ estimates.