Languishing in a prison cell in Central Florida is an inmate who could end up derailing Betty Castor's U.S. Senate race. Sami al-Arian is being held on charges that he financed Islamic Jihad terrorists while a professor at a school Castor headed, the University of South Florida. You'll be hearing a lot about al-Arian, say Democratic insiders. Television ads are being fashioned that slam Castor for not firing al-Arian. Castor refused to dismiss the professor for years after calls he be tossed out and after international publicity about his role in Islamic Jihad.