Twice, "opening arguments" are referenced. Opening statements are presented at the beginning of a trial, closing arguments are made at the end, before the case is given to the jury to be decided.
While escaping from the hospital in an SD-6 helicopter, Jack reveals that he knows Irina had surrendered herself to the CIA, and implies he & Sydney have been in contact with her, since then. This would have revealed them both as double agents for the CIA, against SD-6.