Amitai Etzioni’s contribution to the great drone debate makes the sensible point that drone strikes often offer our leaders a superior alternative to bombers, longer-range missiles and ground raids in places like Yemen and Pakistan. What drone critics miss, Etzioni says, is that all foreign attacks kill noncombatants, alienate locals and undermine their government. Drones (unmanned aerial vehicles is a more accurate but less common usage) do so with less trouble and offer various tactical advantages.

Etzioni is right that drone critics too often imagine that some antiseptic means can meet the strikes’ objectives and thus that we can avoid choosing between lethal and humanitarian goals. (The same can be said of complaints about close-air support in Afghanistan.) Etzioni might have knocked another set of critics: those who want to replace drone strikes with a magical formula that will transform areas like Pakistan’s Northwest Frontier Provinces into stable, peaceful ones.

The trouble with Etzioni’s commentary is that it ignores critics of drone strikes that see the alterative as doing nothing, or at least doing something nonlethal. In that case, the question is whether the humanitarian toll and blowback is worth the benefit of the killing, not whether there is a better way to kill. I say we in the public lack the ability to make that judgment and should oppose the strikes until we have better information.

Etzioni dismisses as pop sociology the concern that drones make warfare costless and therefore more likely. Would, he asks, “we or the people of Afghanistan and Pakistan—or, for that matter, the terrorists—be better off if they were killed in close combat?”

Actually, yes. The argument is that we make more careful judgments about lethal acts when we anticipate more costs to our troops. Free wars, as I noted here, are more likely to be dumb wars. That doesn’t mean we should put troops in harm’s way just to have more skin in the game and improve debate. But we should worry about how the absence of discernible consequences at home makes us more likely to casually bomb people. It is not pop sociology but orthodox price theory that tells us that lowering cost increases demand.

Now that we've mostly quit dividing war powers between governmental branches, cost—human and economic—is one of the few remaining restraints on whimsical war making. Drones are a wildly successful military innovation in part because they minimize that restraint.

The White House justifies increased drone strikes in Somalia with casual assertions that the Islamist insurgents there, the Shabaab group, have begun to target Americans. No congressional committee or even major newspaper presses them to substantiate that claim. We know about the limits on targeting there only because administration officials leak to David Ignatius. The most dovish mainstream position on our war in Afghanistan supports drone bases there in perpetuity, leaving the option of truly exiting Afghanistan and Pakistan’s wars to the fringe. Amid the celebration of our killing of Anwar Awlaki in Yemen last week, the media took just slight notice of “civil-libertarians” and their quaint notion that the due process constitutionally owed to U.S. citizens before their government kills them may exceed a White House assertion in a press conference that their role as a terrorist leader “has been well established”— presumably by a secret memo that the administration wrote itself.

Even most avowed fans of drone strikes should admit that by lowering cost, they preempt debate and make killing easier. That is a problem for democracy.