An instructor at the University of Wisconsin who has said he believes US officials orchestrated the terrorist attacks of Sept. 11, 2001, will be allowed to teach a course on Islam, the school said. Some state politicians had called for the University of Wisconsin-Madison to fire part-time instructor Kevin Barrett after he spoke about his theories on a radio talk show last month. "We cannot allow political pressure from critics of unpopular ideas to inhibit the free exchange of ideas," Provost Patrick Farrell said in a statement Monday. "To the extent that his views are discussed, Mr. Barrett has assured me that students will be free - and encouraged - to challenge his viewpoint." Farrell launched a review after Barrett said he believed the attacks were the result of a conspiracy designed to spark war in the Middle East.