The most important question to ask of the Global War on Terror should be the most simple to answer. Instead, it is a perennial shadow cast over US counter-terror operations since 9/11.

We still don't know, and still must ask: Who exactly is the enemy?

In 2001, the Authorization of Military Force Act told us that the enemy was whoever perpetrated the September 11 attacks and their affiliates. In 2013, President Barack Obama stated that this meant "al Qaeda, the Taliban, and its associated forces." But associated forces was not defined. Administration officials told the New York Times that Obama's method for counting combatants "in effect counts all military-age males in a strike zone." A Justice Department memo released this summer told us that US citizens, too, could be legitimate targets. Then, the Islamic State, a terror group actively disaffiliated with al Qaeda and the Taliban, were included as "the enemy."

"The enemy," then, is whomever gets targeted as the enemy. The validity and legality of these targets is debated post hoc, often after they are dead. A chilling illustration of this comes in the form of a new report from the Bureau of Investigative Journalism, a UK-based organization that tracks US drone usage and the victims of drone strikes. The Bureau's Naming the Dead project makes clear quite how little we know about the casualties of these strikes, which stretch the notion of "targeted" beyond recognition.

The Bureau found that fewer than 4 percent of the people killed by drone fire in Pakistan have been identified by available records as named members of al Qaeda. This doesn't mean, to be sure, that only 4 percent of drone deaths were named members of al Qaeda. Rather, of the killed individuals identified using a variety of sources, only 4 percent matched with already named al Qaeda members. The Bureau spent more than a year looking into 2,379 deaths, using multiple sources including "both Pakistani government records leaked to the Bureau, and hundreds of open source reports in English, Pashtun, and Urdu."

According to that research, only 704 of the 2,379 dead have been identified, and only 295 of these were reported to be members of some kind of armed group. Few corroborating details were available for those who were described solely as "militants." More than a third of them were not designated a rank, and almost 30 percent are not even linked to a specific group. Only 84 of the dead are identified as members of al Qaeda — less than 4 percent of the total number of people killed.

More comprehensive lists of names may well exist in secret CIA and Pakistani government files. But the Bureau's research illustrates the paucity of publicly available knowledge. The upshot, then, is that the US government is asking the public for blind trust while it operates shadow wars on ill-defined targets. Debate over the justifiability of the entire drone program is foreclosed by the glaring absence of traceable felled enemies or innocent collateral damage. Without names, the Bureau rightly contends, we can't even begin the discussion about the viability or success of drone strikes.

"Give us names, and then we can debate over who is or isn't a militant," Bureau reporter Abigail Fielding-Smith told VICE News. Her comment points directly at the two-tiered problem of evaluating this opaque war effort: Not only are the determinations of who gets to be a target broad and shadowy, but it is also unclear whether the casualties wrought even meet these guidelines. It's not sufficient to name the dead, but it is a necessary condition for assessing the function of a war that we understand who is dying.

Follow Natasha Lennard on Twitter: @natashalennard