response to a column that ran in the Los Angeles Times questioning the oversight of drone strikes. "Committee staff has held 28 monthly in-depth oversight meetings to review strike records and question every aspect of the program including legality, effectiveness, precision, foreign policy implications and the care taken to minimize noncombatant casualties." If the congressional committees objected to something, the lawmakers could call CIA leaders to testify in closed investigative hearings. If unsatisfied, they could pass legislation limiting the CIA's actions. Congressional criticism of drone strikes has been rare. However, in June 2012, 26 lawmakers, all but two of them Democrats, signed a letter to Obama questioning so-called signature strikes, in which the U.S. attacks armed men who fit a pattern of behavior that suggests they are involved in terrorist activities. Signature strikes have been curbed in Pakistan, where they once were common, but in 2012 Obama gave the CIA permission to conduct them in Yemen, where an Al Qaeda affiliate that has targeted the United States has established a safe haven in the south. The lawmakers expressed concern that signature strikes could kill civilians. They added: "Our drone campaigns already have virtually no transparency, accountability or oversight." While the Bush administration had put emphasis on killing significant members of al Qaeda, the use of combat drones underwent a quiet and unheralded shift during the Obama Administration to focus increasingly on killing militant foot soldiers rather than high-value targets according to CNN National Security Analyst Peter Bergen. Bergen noted: "To the extent that the targets of drone attacks can be ascertained, under Bush, al Qaeda members accounted for 25% of all drone targets compared to 40% for Taliban targets. Under Obama, only 8% of targets were al Qaeda compared to just over 50% for Taliban targets." Facing the possibility of defeat in the 2012 Presidential election, the Obama administration accelerated work in the weeks before the election to develop explicit rules for the targeted killing of terrorists by unmanned drones, so that a new president would inherit clear standards and procedures. The work to codify U.S. drone policy began in summer 2011. "There was concern that the levers might no longer be in our hands," said one unnamed U.S official. With a continuing debate about the proper limits of drone strikes, Obama did not want to leave an "amorphous" program to his successor, the official said. The effort, which would