Sen. Jeff Flake (R-Ariz.) had it right when he said that he had no clue that the 2001 AUMF would be expanded until its original meaning was rendered moot. “When I voted in 2001 to authorize military force against the perpetrators of the September 11 attacks,” the Arizona senator said, “I had no idea I would be authorizing armed conflict for more than 15 years and counting.”
And yet, nearly 16 years later, a war resolution that was designed to combat the terrorist group behind 9/11 has transformed into a carte blanche to fight every Sunni jihadist group on the face of the earth. All the executive branch needs to do is provide a decent enough case that the terrorist group being targeted is connected in some way, shape, or form to al Qaeda or the Islamic State.
The executive branch has been incredibly successful in convincing members of Congress to buy into that logic—knowing full well that the actual text of the 2001 resolution is quite restrictive. The George W. Bush, Barack Obama, and Donald Trump administrations have all taken advantage of their constitutional authority as Commanders-in-Chief to increase their war powers to the detriment of every other branch of government.