According to the NY Times, US intelligence inside Sudan was so terrible that it is now admitted that they couldn't have known, only "surmised" that the pharmaceutical plant made chemweapons on the side. Sudan supports or at least harbors terrorists, for sure, but there was a sort of institutional demonization of the country inside the US government because of previous warnings that Sudan planned to take the US, including assassinating Anthony Lake. These warnings were false, coming from agents who were taking CIA money and making up their reports (see Graham Greene, Our Man in Havana, John Le Carré, The Tailor of Panama).