WASHINGTON — Facing the possibility that President Obama might not win a second term, his 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, according to two administration officials.
The matter may have lost some urgency after Nov. 6. But with more than 300 drone strikes and some 2,500 people killed by the CIA and the military since Obama first took office, the administration is still pushing to make the rules formal and resolve internal uncertainty and disagreement about when lethal action is justified.
Obama and his advisers are still debating whether remote-control killing should be a measure of last resort against imminent threats to the United States, or a more flexible tool, available to help allied governments attack their enemies or to prevent militants from controlling territory.
Though publicly the administration presents a united front on the use of drones, behind the scenes there is longstanding tension. The Defense Department and the CIA continue to press for greater latitude to carry out strikes; Justice Department and State Department officials, and the president’s counterterrorism adviser, John O. Brennan, have argued for restraint, officials say.
More broadly, the administration’s legal reasoning has not persuaded many other countries that the strikes are acceptable under international law. For years before the Sept. 11, 2001, attacks, the United States routinely condemned targeted killings of suspected terrorists by Israel, and most countries still object to such measures.
But since the first targeted killing by the United States in 2002, two administrations have taken the position that the United States is at war with Al Qaeda and can legally defend itself by striking its enemies wherever they are found.
Partly because UN officials know the United States is setting a legal and ethical precedent for other countries developing armed drones, the United Nations is to open a unit in Geneva early next year to investigate US drone strikes.
The attempt to write a formal rule book for targeted killing began last summer after news reports on the drone program, started under President George W. Bush and expanded by Obama, revealed some details of the president’s role in procedures for compiling ‘‘kill lists’’ and approving strikes.
Though national security officials insist that the process is meticulous and lawful, the president thinks it should be institutionalized.