It has now been 20 years since September 11th, 2001. So we’re bringing you a Peabody Award-winning story from our archives about one sentence, written in the hours after the attacks, that has led to the longest war in U.S. history. We examine how just 60 words of legal language have blurred the line between war and peace. In the hours after the attacks of Sept. 11, 2001, a lawyer sat down in front of a computer and started writing a legal justification for taking action against those responsible. The language that he drafted and that President George W. Bush signed into law - called the Authorization for Use of Military Force (AUMF) -  has at its heart one single sentence, 60 words long. Over the last decade, those 60 words have become the legal foundation for the "war on terror." In this collaboration with BuzzFeed, reporter Gregory Johnsen tells us the story of how this has come to be one of the most important, confusing, troubling sentences of the last two decades. We go into the meetings that took place in the chaotic days just after 9/11, speak with Congresswoman Barbara Lee and former Congressman Ron Dellums about the vote on the AUMF. We hear from former White House and State Department lawyers John Bellinger & Harold Koh. We learn how this legal language unleashed Guantanamo, Navy Seal raids and drone strikes. And we speak with journalist Daniel Klaidman, legal expert Benjamin Wittes and Virginia Senator Tim Kaine about how these words came to be interpreted, and what they mean for the future of war and peace. Finally, we check back in with Congresswoman Lee, and talk to Yale law professor and national security expert Oona Hathaway, about how to move on from the original sixty words. Original episode produced by Matt Kielty and Kelsey Padgett with original music by Dylan Keefe. Update reported and produced by Sarah Qari and Soren Wheeler. Special thanks to Brian Finucane. Support Radiolab by becoming a member today at Radiolab.org/donate.