Presidential counterterrorism adviser John O. Brennan is compiling the rules for a war the Obama administration believes will far outlast its own time in office. The playbook," as Brennan calls it, will ... cover the selection and approval of targets from the "disposition matrix," the designation of who should pull the trigger when a killing is warranted, and the legal authorities the administration thinks sanction its actions in Pakistan, Yemen, Somalia and beyond. Brennan is the principal architect of a policy that has transformed counterterrorism from a conventional fight centered in Afghanistan to a high-tech global effort to track down and eliminate perceived enemies one by one. What was once a disparate collection of tactics ... has become a White House-centered strategy with Brennan at its core. Brennan is leading efforts to curtail the CIA's primary responsibility for targeted killings. Still, during Brennan's tenure, the CIA has carried out hundreds of drone strikes in Pakistan and opened a new base for armed drones in the Arabian Peninsula. Brennan wields enormous power in shaping decisions on "kill" lists and the allocation of armed drones, the war's signature weapon.