A quick Google search and I didn't find what you must have been referring to, but I found plenty of references to attempts to do it before. One reference shows that Bill Clinton lost his effort to use executive privilege to prevent "senior aides" from testifying. Later in that reference [ http://74.125.93.132/search?q=cache:...&ct=clnk&gl=us ] they mention his (Clinton's) personal secretary WILL testify. Doesn't specifically mention if Clinton tried to cover the secretary with "E.P."