Bolton can be called to testify and the invoke EP on a question-by-question basis. Trump would have us believe EP allows him to give a lifetime ban to anybody whose ever worked with him in any capacity. It doesn’t work that way. For starters, EP doesn’t apply to criminal activity.
EP has grown completely out of control It’s a “right” that was invented by the Executive Branch, with the participation of the Courts, that has no Constitutional or statutory basis.
Also something to keep in mind: none of the people ordered by Trump to not testify has actually used the words “executive privilege”. We’ve yet to hear any legal basis for their obstruction.
Been trying to find a source for who has actually claimed EP, and it seems like only McGahn has used the argument in a court (and his claim was rejected).
Below is a good article on the topic. A key paragraph:
Given these principles and earlier OLC arguments, it would appear that some of the immunity claims advanced by President Trump on behalf of his aides seek to stretch the law of executive privilege beyond its acknowledged boundaries. Indeed, in the case of some witnesses who have been instructed not to testify, the stretch is extreme. In particular, claiming immunity for staff who are not direct reports to the president, for members of the cabinet or their staff, and for people who have left the government would require the courts to go far beyond rethinking the availability of subpoena immunity for the closest active presidential aides.