Death in the border regions of Pakistan can come from up close, at knifepoint or underfoot. Or it can come silently from above, arriving on the wings of U.S. Predator and Reaper drones that surveil the rugged terrain region and unleash Hellfire missiles on targets three miles below.
The Obama administration's stepped-up use of unmanned aerial vehicles to target Taliban and al Qaeda leaders in hard-to-reach parts of Pakistan, as well as Somalia, Yemen and Afghanistan, far exceeds the Bush administration's, and has put the president's stamp on the war on terror. It's also raised legal and ethical questions, with some critics claiming that the drone program violates international law and constitutes illegal assassinations.
On Thursday night, Harold Koh, the State Department legal adviser, answered critics publicly, laying out the administration's legal argument in a speech to ASIL, the American Society of International Law.
The argument, according to Koh, is that because the United States is at war, and al Qaeda has stated its continued goal to attack the United States, the drone killings are justified as self-defense, as long as the killings meet certain criteria.
To meet those criteria, the targets must be distinct and they must be proportional, he said, which means drones cannot bomb civilian targets and cannot use more force than is needed to kill the specific person in the crosshairs of the remote pilots thousands of miles away.
The argument, which many national security scholars have eagerly awaited, did not satisfy some critics, according to NPR's Ari Shapiro, who reported on the speech on Friday. It was also noted on many legal blogs, such as The Volokh Conspiracy and The Journal of National Security Law and Policy.
The use of drones has put the administration at odds with groups like the ACLU, an administration ally which has been increasingly critical of the White House on national security issues, and has sued for documents related to the drone program.
But the speech was not only aimed at domestic audiences. Last year, Philip Alston, the Special Rapporteur on extrajudicial, summary or arbitrary executions for the United Nation, warned the U.S. that its use of drones would be considered a violation of international law unless the U.S. was able to prove appropriate precautions and accountability.
One set of critics that Koh's words will be unlikely to placate are critics within Pakistan, where the drones have infuriated many Pakistanis and fanned anti-American sentiments because of the wide-spread view that the missions violate Pakistani sovereignty.
One solution to that problem would be for Pakistan to obtain its own. On Thursday, Secretary of Defense Robert Bates said the U.S. hopes to export the closely-guarded technology, telling Senators at a hearing that allies had expressed interest.
So far, one two allies -- Italy and the United Kingdom -- had bought drones from the U.S., he said in answer to a question from California Senator Diane Feinstein. He said he was worried about drone technology falling into hands of "non-state actors" who might use them for terrorism.
"There are other countries that are very interested in this capability and frankly, it is, in my view, in our interest to see what we can do to accommodate them,"Gates said. "But I share your concern about the possibility of the transfer of technology or about these capabilities getting into the hands of those who are our adversaries."