One hot summer evening in 2009, in a small village in the remote Pakistani tribal agency of South Waziristan, a pair of Hellfire missiles fired from an unmanned Predator drone slammed into a house, killing the chief of the Pakistani Taliban, Baitullah Mehsud, along with his wife. About a year later, in May 2010, down a dirt road from Miran Shah, the main town in North Waziristan, a missile from another Predator killed Mustafa Abu al-Yazid (known as Saeed al-Masri), a founding member of al Qaeda, along with his wife and several of their children.
These drone strikes were successful in killing high-level leaders of the Taliban and al Qaeda. But few are. On average, only one out of every seven U.S. drone attacks in Pakistan kills a militant leader. The majority of those killed in such strikes are not important insurgent commanders but rather low-level fighters, together with a small number of civilians. In total, according to our analysis, less than two percent of those killed by U.S. drone strikes in Pakistan have been described in reliable press accounts as leaders of al Qaeda or allied groups. Not a single drone strike had targeted Osama bin Laden before he was killed by U.S. Navy SEALs on May 2. Meanwhile, al Qaeda's second-in-command, Ayman al-Zawahiri, has not been targeted by a drone since 2006.
The U.S. drone program has its roots in the late 1990s, when unmanned -- and unarmed -- aircraft tracked and spied on al Qaeda in Afghanistan. After 9/11, then U.S. President George W. Bush ordered U.S. drones, at that point equipped with missiles, to kill leaders of al Qaeda, first in Afghanistan and later in Yemen and Pakistan. From June 2004, when the strikes in Pakistan began, to January 2009, the Bush administration authorized 44 strikes in the rugged northwestern region of Pakistan. Since assuming office, Barack Obama has greatly accelerated the program, likely as a result of better on-the-ground intelligence in Pakistan. In just two years, the Obama