The New York Times reported Monday that the Obama administration has decided to expand its war on terror by designating the Somali militant group al-Shabaab as a target under the 2001 Authorization for the Use of Military Force. That authorization, which was originally intended as a green light to go after the perpetrators of 9/11, will now provide legal justification for an escalating campaign of airstrikes in the Horn of Africa.

Al-Shabaab didn’t even exist in 2001, but the AUMF has proven to be an extraordinarily flexible document, serving as the legal basis for attacks against “associated forces” of al-Qaida throughout the world, most notably ISIS, which is actually a rival of the terror network that the AUMF was drawn up to address. How has the Obama administration justified this? It has taken the self-serving position that although it would like Congress to pass a new resolution authorizing force against ISIS, it doesn’t actually need one. And so far, it’s been right: Just last week, a federal judge dismissed a lawsuit filed by a U.S. Army captain accusing the administration of waging the war against ISIS illegally.

Obama pledged in 2013 to replace the AUMF with something more tailored and specific, but disagreements with Congress over the what a new agreement would look like and the deteriorating conditions in Syria, Iraq, Libya, and Afghanistan have led the administration to not only continue waging war in those countries under the AUMF, but to expand the list of targets it covers. As Monday’s Times story notes, the 2001 authorization passed by Congress was never meant to authorize attacks against “every Islamist militant in the world,” but that’s quickly what it’s becoming.

With the exception of a few voices in Congress (including, notably, Sen. Tim Kaine, though he didn’t make it much of an issue when he was running for vice president), the administration never faced much political pressure on the legality of its expanding war on terror. Republicans opposed even minor attempts to limit the scope of counterterrorism activities. Most Democrats were wary of criticizing the administration and perhaps assumed that Obama would exercise his extraordinary powers responsibly.

Now that a man who made “bomb the shit out of them” a campaign pledge and thinks he should be allowed to kill terrorists’ families is about to enter the Oval Office with few limits on when and where he can wage an ill-definied war, Democrats may wish they had done their jobs.