Peter Bergen of the New America Foundation, which is the leading compiler of information about US drone strikes, made this interesting comment in his testimony yesterday before the Senate Judiciary Committee:

The drone program has increasingly evolved into a counterinsurgency air platform, the victims of which are mostly lower-ranking members of the Taliban (Pakistan) and lower-level members of al-Qaeda and associated groups (Yemen). In 2010, a militant told a New York Times reporter, "It seems they really want to kill everyone, not just the leaders."

In September 2012, President Obama told CNN that drone strikes were only used in "[situations] in which we can’t capture the individual before they move forward on some sort of operational plot against the United States." Clearly the threshold to mount drone strikes is far lower than this standard would suggest given the fact that overwhelmingly the victims of the strikes are lower-level militants who do not have the capacity to plot effectively against the United States.

Under Bush, about a third of all drone strikes in Pakistan killed a militant leader compared to less than 13 percent from the time Obama took office to mid-April 2013. While Bush sought to decapitate the leadership ranks of al-Qaeda, Obama seems to be aiming to collapse the entire network of allied groups, such as Tehrik-i-Taliban Pakistan (TTP), the Pakistani Taliban.