My reading was they can't use testimony or notes from advisors in the executive branch who are helping the President perform an official act. I.e. anything tha

My reading was they can't use testimony or notes from advisors in the executive branch who are helping the President perform an official act. I.e. anything that would have a chilling effect on the President's ability to direct the executive Outside of that, e.g. campaign staff, is a different matter. And I believe there's already a distinction between government employees and campaign employees (probably for campaign finance reasons).