Hadi's acknowledgement of the drone attacks also underlies some of the differences between Pakistan and Yemen. The strikes in Yemen have been more limited than in Pakistan, and until recently, have faced fewer allegations of collateral damage and thus less public outrage. More fundamentally, the strikes in Yemen are directed against a group that poses a threat to the central government, and thus gives Hadi more reason to support foreign intervention.

That could be changing, however, particularly in light of a September strike that resulted in more than a dozen civilian casualties, according to local reports. In another controversial operation, a 2011 strike targeting Yemeni cleric Anwar al-Aulawi also killed his American-born 16-year-old son, a U.S. citizen.

While many emphasize the benefits of drones in taking the pilot out of harm's way, the real advantage derived from unmanned vehicles may hinge more on politics than technology: The lack of a pilot in the cockpit allows the U.S. to conduct operations in countries where it would never consider flying armed combat missions. An armed F-16 sent into Pakistan or Yemen to hunt terrorists might be unthinkable for those countries, but an armed drone operated by the CIA is more politically palatable.

Having the CIA run its own drone operations has allowed the U.S. government to conduct operations with relative impunity for more than a decade. While it now acknowledges that such strikes take place, the issue is not debated in open congressional committee hearings (since they fall within the purview of the Capitol Hill intelligence committees) nor discussed publicly in any great detail by administration officials. In essence, the combination of UAVs and CIA cover has allowed the U.S. to extend the battlefield far beyond where the U.S. military is publicly engaged in combat operations, and into countries where the U.S. in years past would have never considered conducting lethal operations.

Sharon Weinberger Washington