US President Barack Obama is now seeking to influence global guidelines for drone use as China and other countries pursue their own programmes.
The United States was the first to use unmanned aircraft fitted with missiles to kill militant suspects in the years after the September 11 2001, attacks on New York and Washington.
But other countries are catching up. China's interest in unmanned aerial vehicles was displayed in November at an air show. According to state-run newspaper Global Times, China had considered conducting its first drone strike to kill a suspect in the 2011 murder of 13 Chinese sailors, but authorities decided they wanted the man alive so they could put him on trial.
"People say what's going to happen when the Chinese and the Russians get this technology? The president is well aware of those concerns and wants to set the standard for the international community on these tools," said Tommy Vietor, until earlier this month a White House spokesperson.
As US ground wars end—over in Iraq, drawing to a close in Afghanistan—surgical counterterrorism targeting has become "the new normal", Vietor said.
Amid a debate within the US government, it is not yet clear what new standards governing targeted killings and drone strikes the White House will develop for US operations or propose for global rules of the road.
Obama's new position is not without irony. The White House kept details of drone operations—which remain largely classified—out of public view for years when the US monopoly was airtight.
That stance is just now beginning to change, in part under pressure from growing public and Congressional discomfort with the drone programme. US lawmakers have demanded to see White House legal justifications for targeting US citizens abroad, and to know whether Obama thinks he has the authority to use drones to kill Americans on US soil.
On Friday, a three-judge federal appeals court panel unanimously ruled that the CIA gave an inadequate response to a lawsuit brought by the American Civil Liberties Union seeking records about drone strikes. The CIA had said it could neither confirm nor deny whether it had drone records because of security concerns.
The judge who wrote the ruling noted that the president had publicly acknowledged that the United States uses drone strikes against al-Qaeda.
Strikes by missile-armed Predator and Reaper drones against terrorism suspects overseas began under former president George Bush and were expanded by Obama.
The ramp-up started in 2008, the last year of Bush's term, when there were 35 air strikes in Pakistan, and escalated under Obama to a peak of 117 in 2010, according to The Long War Journal.
That jump in use of armed drones resulted from the authorisation to use "signature" strikes, which allowed targeting terrorism suspects based on behavior and other characteristics without knowing their actual identity, a US official said on condition of anonymity.
Caitlin Hayden, a spokesperson for the White House National Security Council, said the administration is committed to explaining to Congress and the public as much as possible about its drone policies, including how decisions to strike are made.
"We are constantly working to refine, clarify, and strengthen the process for considering terrorist targets for lethal action," Hayden said.
The administration recognises "we are establishing standards other nations may follow", she said.
James Lewis, a senior fellow at the Centre for Strategic and International Studies think tank, said other countries, including Russia, have unarmed reconnaissance drones. China says it has an armed drone, but "we don't know if it works", he said.
"Getting agreement on the applicability of existing humanitarian law to the new technologies is crucial," he said, because China and Russia do not endorse applying laws of armed conflict to new military technologies.
One of the Obama administration's goals is to "regularise" the drone programme, making it more a part of accepted US practice in the future, Lewis said. "This is going to be part of warfare."
While the Obama administration moves toward refinement and transparency of standards, drone strikes continue to spark outrage in countries where they are conducted. Washington has sought to portray civilian casualties from drone strikes as minimal, but groups collecting data on these attacks say they have killed hundreds of civilians.
A UN human rights investigator who is looking into drone strikes worldwide said on Friday the US campaign had violated Pakistan's sovereignty.
One focus of US officials' internal debate is whether to shift drone operations to the Pentagon from the CIA.
That would allow the CIA to return to more traditional operations of espionage and intelligence analysis, and put the killing of terrorism targets in the hands of the military.
It would probably be a "phased approach" that would account for differences in the threat and political sensitivities, said a second US official. "There would have to be some tailoring."
In Pakistan, where the US military is not in ground combat, the Obama administration would probably not want drone strikes to appear as being conducted by the military.
In Yemen, there may not be the same sensitivities. US military personnel are on the ground working with Yemenis in counterterrorism operations.
The United States has also carried out drone strikes in Afghanistan, Iraq, Libya and Somalia.
"I think if they moved it, not as a covert action programme, but one of the tools of the warfighter, then the result of it is probably going to be more public exposure about what they are doing," Stephen Hadley, national security adviser under Bush, said.
The "centre of gravity" in internal administration debates is the goal of greater consistency on how drone strikes are managed, decided upon, and executed, the second official said. - Reuters