International politics play a role in that decision. The US government’s official denial, Mayer continued, “is in large part in deference to the Zardari administration in Pakistan, which prefers to mislead the Pakistani public about its acquiescence to the US drone strikes.” That acquiescence was always conditional and uncomfortable between the two allies, each of whom harbors suspicions of the other. In mid-April, Pakistani officials demanded that the CIA dramatically reduce its presence in Pakistan and that drone strikes cease, according to news reports, but, like so much of the US operations in Pakistan, it is unclear what is actually happening there.

In an interview with this author published by Newsweek earlier this year, former CIA acting general counsel John A. Rizzo pulled back the curtain a little and described the protocol set up to authorize a drone strike. One of the approximately ten lawyers in the CIA’s counterterrorism unit would review intelligence information and draft a memo asserting that an individual posed a risk to the security of the United States. After weighing the evidence in the memo, Rizzo, who retired in December 2009, would sign his name, noting that he “concurred.” The strike was then authorized.

Despite Rizzo’s unusual candor in that interview, he and other officials have fought to keep most information about the Pakistan drone war out of the public eye. Journalists have been unable to get answers to legal questions such as on what basis the government decides to kill. This is known as “distinction” in international law; in other words, how are those CIA lawyers discriminating between civilians and non-civilians who pose a grave threat to the United States? Also, how many civilian deaths can be justified? This is the question of “proportionality” in international law.

At this point, so little has been written about the way the CIA chooses its targets and executes its missions that some legal scholars argue it is impossible to know whether the program is legal. “I’ve been concerned that we don’t have the right kind of permission from elected officials,” said Mary Ellen O’Connell, an international law professor at the University of Notre Dame Law School. “Pakistan is not Somalia. They have a government we respect. It can be a weak government, but international law doesn’t allow you to act as if there is no government.”

A spokesman for the White House National Security Council, who spoke only on condition he not be named, rebuffed questions about why the administration refuses to speak with reporters on the record about the program. “You’re going to have a lot of people on the outside, and they all love to talk,” he said. “We can’t do that.” And, the official added, if outsiders are talking about the drone war, “that means they don’t know very much.”

Ignatius, of the Post, explained that Obama administration officials are sometimes willing to discuss drone operations in an attempt to promote the White House’s counterterrorism strategy. In February 2010, for instance, Ignatius was able to write a detailed account of the escalation of drone strikes because officials were eager to demonstrate that Obama was more aggressive in his pursuit of al Qaeda than Bush was.

“These rules about covert activities can be bent when it becomes politically advantageous,” Ignatius said. “When it suits them, you get quite a detailed readout.”

Yet rather than demand more consistent transparency from officials or undertake investigations that delve into the program, journalists often have simply relied on what US and Pakistani officials have told them. When reporters depend too heavily on government sources to report on a war, they end up following the narrative that White House officials have created, and in this way provide a one-sided view that obscures reality. The aerial strikes in Pakistan have been underway for nearly a decade, and yet many questions surrounding their use remain unasked and unanswered.

A Shadowy World

The Pakistani media have covered civilian deaths from drone attacks more consistently than Western reporters. Tallies from leading Pakistani media organizations report that as many as eighteen hundred civilians and mid- and low-level fighters have been killed in attacks since Obama took office, as compared to the twenty “high-value” militants the US managed to kill in that period, according to New America Foundation researchers. The number of civilians and low-level militants who have been killed are sketchy and have thus far proved impossible for US journalists to verify. News stories often cite anonymous Pakistani officials in their accounting of the dead.

“You’re left with this kind of shadowy world, and you pick up every discrete fact that you can—knowing all the while that you’re only getting a glimpse of something and not the whole thing,” said Yochi Dreazen, a former Wall Street Journal reporter and now a senior correspondent for National Journal.

Tara McKelvey is the author of Monstering: Inside America's Policy of Secret Interrogations and Torture in the Terror War and is a 2011 Guggenheim Fellow. Research assistance was provided by Jed Bickman of the Investigative Fund at The Nation Institute, which also provided financial support for preparation of this article.