(CNN) Former FBI Director James Comey is expected to testify next week before the Senate intelligence committee, but President Donald Trump may try to stop him by asserting executive privilege. It would not work. Trump cannot use executive privilege to keep Comey from testifying about discussions that may point to potential misconduct, and that's especially true now that Trump has already made those discussions public. Although The New York Times reported that the President is not planning on doing so, he could change his mind, according to two senior administration officials. Executive privilege is not a well-defined legal concept. You can't find the words "executive privilege" anywhere in the Constitution. It's not written down in any federal statute, and it's not part of the rules of evidence.