Who exactly is the enemy in the continuing U.S. war against terrorism?
In some cases, the answer is: It's a secret.
When the United States began its war against Al Qaeda after the attacks of Sept. 11, 2001, the identity of the enemy was clear: Osama bin Laden and his followers, and the Taliban who protected them in Afghanistan. Congress quickly passed a resolution authorizing President George W. Bush to use "all necessary and appropriate force" against anyone who "planned, authorized, committed or aided" the 9/11 attacks, plus anyone who harbored them.
That resolution, called the Authorization for the Use of Military Force, remains the legal underpinning for most counter-terrorist operations today.
Since 2001, however, the target list has grown. Al Qaeda offshoots have sprung up in Yemen, Somalia, Libya, Mali and, now, Syria. Many of their members had nothing to do with the attacks of 9/11. Most appear more interested in seizing power in their own countries than in striking the United States. Before he died, Bin Laden even scolded his followers in Yemen for spending too much time on local politics and too little on international terrorism.
Nevertheless, both the Bush and Obama administrations decided that the 2001 authorization (the AUMF, for short) covered any group affiliated with Al Qaeda that plans operations against the United States or U.S. interests abroad.
In many cases, that's a reasonably clear standard. When Al Qaeda's Yemen affiliate put a terrorist with explosives in his underwear on a flight to Detroit, the target was plainly the U.S.
But other cases are more ambiguous. Does the Shabab militia in Somalia qualify? They are Islamic terrorists and a danger to East Africa, but they pose little threat to the United States. Does Ansar al Sharia, the group that attacked a U.S. mission in Libya last year but has loose ties to Al Qaeda, fit in? What about Al Nusra Front in Syria, a group born as part of the uprising against Bashar Assad?
All are violent extremists who might gladly kill Americans given the opportunity. But Congress certainly didn't have them in mind when it approved the AUMF.
"None of us, not one who voted for it, could have envisioned we were voting for the longest war in American history, or that we were about to give future presidents the authority to fight terrorism as far-flung as Yemen and Somalia," Sen. Richard J. Durbin (D-Ill.) said recently.
So Congress is, belatedly, pondering whether the 12-year-old law needs to be revised. For some, like Durbin, the problem is that the resolution has turned into a blank check. For others, such as Sen. Lindsey Graham (R-S.C.), the problem is that the AUMF doesn't authorize action against terrorists who aren't affiliated with Al Qaeda. But both parties agree that Congress ought to take a more explicit role in writing the rules for a war that appears likely to drag on for another decade or more.
At a stormy hearing of the Senate Armed Services Committee last month, Sen. Carl Levin (D-Mich.), the panel's chairman, asked if he could see a list of organizations the administration considers Al Qaeda affiliates.
Pentagon counter-terrorism chief Michael Sheehan sounded unenthusiastic. "A lot of these groups … have very murky membership," Sheehan said. "They change their name and they lie and obfuscate their activities. So I think it would be difficult for the Congress to get involved in trying to track the designation of which are the affiliate forces. We know when we evaluate these forces what they're up to."
That answer — "trust us," in effect — didn't mollify Levin. He asked again for a list.
"I'm not sure there is a list per se," Sheehan replied. But he promised to put one together.
I asked both the committee and the Pentagon this week whether the list could be publicly released. Neither gave a clear reply. If there is an enemies list, it is still secret.
If Congress does revise the AUMF, it's unlikely to make much of a practical difference in the way the United States fights terrorists. Most members of Congress still support drone strikes against known terrorists, even U.S. citizens like Anwar Awlaki, who was killed by a drone strike in Yemen in 2011. They'd just like to be asked for permission before the war expands to new countries, such as Mali, where the United States aided French forces earlier this year.
The Constitution and international law give the president the power to act in self-defense against any imminent threat, even without an AUMF. And, as University of Texas law professor Robert M. Chesney notes, the Obama administration has already interpreted "imminent threat" to mean something closer to any "continuous threat," not just attacks that are about to happen.
So when President Obama endorsed the idea of revising the AUMF in his speech on counter-terrorism last month, he wasn't giving up much. Congress was already looking at the issue.
As Obama has made clear in Afghanistan and Syria, he's looking for ways to get out of old wars, not into new ones. The effect, if any, will mostly be to limit the freedom of Obama's successor to use force.
But there is one thing the incumbent president can do: He can tell his Pentagon to be clearer and less secretive about the criteria it uses to decide which terrorists merit the application of U.S. military force. If there's an enemies list, Congress and the public have a right to see it — a right to know with whom we're at war.