Seventeen years ago the US went to war on the strength of a single sentence: 60 words that were written, debated, and voted upon before the US even knew for certain who was behind the 9/11 attacks. In those panic-stricken early days, action mattered more than knowledge. And on Sept. 14, 2001, three days after the attacks and with the rubble in New York and Washington still smoking, Congress passed the Authorization for Use of Military Force, or AUMF, by an overwhelming margin: 98–0 in the Senate, and 420–1 in the House.
The one sentence at the heart of the AUMF has dramatically altered the world in which we live. It gave the president — any president — extraordinary power, which has since been passed down from administration to administration. Because Congress didn’t yet know who the US would be fighting, the sentence didn’t specify which groups the president could target. Nor did the AUMF put a clock on the war or give it any geographical limits. The details, Congress said, were up to the president who, as the text of the sentence reads, “is authorized to use all necessary and appropriate force against those nations, organizations, or persons he determined planned, authorized, committed or aided the terrorist attacks that occurred on September 11, 2001, or harbored such organizations or persons in order to prevent any future acts of international terrorism against the United States by such nations, organizations or persons.”
Those 60 words have been the legal foundation for nearly every counterterrorism operation three successive administrations — Republican and Democratic — have conducted over the past 17 years. Everything from Guantanamo Bay and the invasion of Afghanistan to drone strikes, SEAL raids, and secret renditions, even the war against ISIS — a group that didn’t exist on 9/11 — is based on those 60 words.
A lot has changed since 2001. Barack Obama went from the Illinois Statehouse to eight years in the White House before passing the baton to Donald Trump. Al-Qaeda has splintered into affiliates and franchises in dozens of countries. Osama bin Laden is dead, and ISIS has risen, fallen, and looks to be rising again. Only that sentence has remained the same.
But while the text hasn’t changed, its meaning has. As the security threat evolved, so too did each successive president’s interpretation of those 60 words. One of the first expansions, under the Bush administration, was the idea of “associated forces.” Basically, this meant that instead of fighting just al-Qaeda, who had carried out 9/11, or the Taliban, who had harbored them, the US could target anyone who was allied with either al-Qaeda or the Taliban. This had the effect of expanding the war from two enemies into a war with dozens, many of which had only tenuous ties to 9/11.
The Obama administration stretched the AUMF even further, interpreting the text to cover the war against ISIS in Iraq and Syria. The fact that ISIS hadn’t existed on 9/11 or that it was, at times, fighting al-Qaeda, didn’t matter. Instead of a messy legislative battle with a Republican Congress, the Obama administration used an old law to fight a new war.
Like his predecessors, President Trump has taken an expansive reading of the AUMF, preserving maximum flexibility and authority for the executive branch. Indeed, even under Obama, that was one of the major stumbling blocks to getting a new AUMF. No president, whether Obama or Trump, wants Congress to rework the AUMF in a way that gives the executive less power or fewer options. By building so much policy on so little law the US has backed itself into a corner. Any attempt to restructure the 60-word foundation, bringing a 2001 law in line with 2018 realities, risks unraveling much of what the US has done. The 60 words of the current AUMF are broad enough and vague enough that each administration can read into them what it wants.
For the Trump administration, that has meant a general loosening of restraints: on who can be targeted, and where they can be targeted, all while doing away with “high-level vetting” of the targets. In Yemen, for example, the Trump administration declared three governorates “areas of active hostilities” — 21st-century military speak for battlefields — effectively widening the range of possible targets. Not surprisingly, given fewer restraints, the number of US strikes in Yemen jumped from just over 30 in 2016, Obama’s final year, to more than 130 in 2017, Trump’s first year.
In Syria, the Trump administration has also claimed that a range of actions, from shooting down a Syrian government jet to targeting Iranian drones — aircraft from two countries that were not remotely involved in 9/11 — were also covered by the AUMF. The idea is that if the AUMF covers US actions against ISIS, as the Obama administration argued, then it also covers any actions of self-defense the US takes while fighting ISIS. Of course, when the US shot down the Syrian jet in June 2017 it wasn’t threatening US troops, but rather US-backed local forces, which are afforded similar protections, further broadening troop-protection considerations and what counts as self-defense.
Now the Trump administration may be looking to be using the umbrella of the AUMF to push back against Iran. This past week the US announced that it was reinforcing a small base in southern Syria, where it trains local fighters to fight ISIS. But as Greg Jaffe, a national security reporter at the Washington Post, pointed out, this is less about ISIS than it is about disrupting Iranian supply lines. Andrew Exum, a former deputy assistant secretary of defense for Middle East policy under Obama, added: “We could tenuously justify [this base] via the 2001 AUMF. Repurposing this to counter Iran is a shift in strategy — and tough to see how this is legal.”
But 17 years after the AUMF was passed, that is where we are at: multiple wars with the potential to morph into new ones. One of the fundamental lessons of the post-9/11 world is: The longer these wars last, the more enemies there will be to fight.
What started as a war against al-Qaeda and the Taliban — which now controls more territory in Afghanistan than at any point since 2001 — has been stretched and stretched again to include first associated forces, and then ISIS, and now maybe even Iran and Syria.
Perhaps the most disturbing fact about the AUMF is that no one knows who the US is actually at war with. In October 2017, four US soldiers were killed in an ambush in Niger. For days after the attack, legal scholars, journalists, and policy wonks questioned whether the soldiers were deployed under the AUMF and, if so, which group they might be fighting. Secretary of Defense James Mattis eventually told Congress the soldiers weren’t deployed under the AUMF, but the initial uncertainty was telling. Even the most informed among us don’t know who we are fighting.
This past week, the US State Department designated an al-Qaeda-affiliated group in Mali as a terrorist organization. Is the US at war with them? Hard to say: maybe, maybe not? But as Lara Seligman of Foreign Policy reports, the US is about to start flying armed drones out of a base next door in Niger. Will the targets be militants in Libya? Mali? Both?
Seventeen years ago, Congress gave the president this open-ended authority, and only Congress can take it back. But the further we drift from 9/11, the harder that will be. The US has built years of counterterrorism policy on the vague and fluid foundation of 60 ambiguous words, which have spawned a war without end.