Micah Zenko, a senior fellow at the Council on Foreign Relations, is the author of "Red Team: How to Succeed By Thinking Like the Enemy." He is on Twitter.

In January 2009, when President Obama came into office, he inherited two controversial covert counterterrorism programs from George W. Bush: the rendition and harsh interrogation (including torture) of terrorist suspects, and the use of drones to kill terrorist suspects outside of traditional battlefields. Two days after taking the oath of office, Obama signed an Executive Order, which revoked the Bush-era directives authorizing torture, and reemphasized international conventions and federal laws prohibiting torture. The following day, Obama authorized two Central Intelligence Agency drone strikes in northwest Pakistan, which, combined, killed an estimated one militant and 10 civilians, including between four and five children.

Troubling questions endure about who is targeted, how sure we are of who is being killed and what oversight of the program is enforced.

Obama’s embrace and vast expansion of drone strikes against militants and terrorists will be an enduring foreign policy legacy. Whereas President George W. Bush authorized approximately 50 drone strikes that killed 296 terrorists and 195 civilians in Yemen, Pakistan and Somalia, Obama has authorized 506 strikes that have killed 3,040 terrorists and 391 civilians. (Using the average estimates provided by three non-governmental organizations.) A technology developed and matured shortly before 9/11 to kill one individual, Osama bin Laden, became the default tactic for a range of counterinsurgency and counterterrorism missions outside of traditional battlefields.

More consequential than the growth in drone strikes, is the Obama administration’s efforts to institutionalize and normalize the practice. Three years into office, Obama took the meaningful step of acknowledging supposedly “covert” strikes in Pakistan, something that his predecessor had never done. Subsequently, he and his senior aides provided carefully scripted language that served as the policy framework and legal basis for lethal counterterrorism operations. These purported “reforms” were formalized by President Obama in a May 2013 speech and accompanying presidential policy guidance. However, there is no evidence that most reforms were ever implemented, and officials emphasized that they did not apply to C.I.A. drone strikes in Pakistan, where roughly 40 percent of all nonbattlefield drone strike have since occurred.

There remain troubling, unanswered aspects of drone strikes, in particular how the policy of “signature strikes”— killing anonymous men who appear to be associated with terrorist or militant armies through observable behavior — comport with the bedrock principle of distinction founded in international humanitarian law. That the United States does not know who it targets with drones is made glaringly obvious from the fact that of eight U.S. citizens killed in U.S. drone strikes, only one was knowingly targeted: Anwar al-Awlaki. Indeed, a central component of Obama’s drone warfare legacy will be the unfilled gap between how his administration has justified drone strikes and how they are conducted.

Ultimately, Obama succeeded in making Americans comfortable with drone strikes, as they are generally supported by the American public (though opposed throughout the world), and wildly popular in Congress. Americans will never know much more about these operations than what the Obama administration has selectively revealed, because, unlike the C.I.A. rendition program (which involved 136 victims), drone strikes (which have killed 3,922 people) occurred under both Republican and Democratic presidents. And there is no interest in Washington to fully investigate government programs that both political parties are directly responsible for.



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