WASHINGTON, D.C.: Fred Thompson may not have his star witness after all. When Senator John Glenn sprung the tantalizing news on the eve of the hearings that key suspect and Democratic fundraiser John Huang might testify before the Senate campaign finance committee, Thompson's show looked to be starting off with fireworks. But Huang, who is demanding partial immunity as his price, may never get to the witness stand, now that Attorney General Janet Reno has announced her opposition to the deal. Granting Huang even partial immunity, she argued, may interfere with her ongoing investigation into campaign finance irregularities. "It's basically the Ollie North rule," says TIME's John Dickerson. "North had an indictment thrown out because the partial immunity he had been granted wound up being treated as total immunity. It's just too complicated legally. And Reno's worried that she'll lose Huang." Thompson's worried too. His proposed compromise: let Huang testify without immunity, answering only the questions that he will agree to discuss. Huang has already offered to freely testify about whether he passed sensitive information to the Chinese government while working as a Clinton appointee with a security clearance at the Commerce Department. The real question, of course, is whether Huang will risk giving up anything of value while facing a possible Justice Department investigation.