Palin was referring to Ayers while on her campaign trail when she said Obama was "palling around with terrorists."
On Monday, Ayers finally fired back, saying he became "an unwitting and unwilling participant in this election," according to the Washington Post.
"Not only did I never kill or injure another person, but the Weather Underground in its six-year existence never killed or injured another person," he said during a speech at the Georgetown University Law Center. "We did something that was extreme. Some of you would call it not only extreme but kind of nuts. You might call it off the track. You might call it crazy. You might call it defying of common sense. It was certainly illegal. To call it terrorism stretches the definition of terrorism to everything you don't approve of."
Ayers went on to call the Sept. 11 attacks "vile," but then said the "flattening of Fallujah" by the U.S. military could also be labeled as "terrorism," the Post reported.
Ayers spoke to about 60 people at the law school and another 400 at All Souls Unitarian Church, a venue that replaced Busboys and Poets due to an increased demand to listen to his speech.