Answer:
President Richard Nixon believed about executive privilege that he, as President, had the right to withhold information from other government branches (the legislative and judicial) to preserve confidential communications within the executive branch and to secure the national interest.
Step-by-step explanation:
President Nixon claimed this "Executive Privilege" during the United States v. Nixon case (1974) in which he was accused of being involved in the Watergate Scandal (1972). When the Supreme Court ordered him to deliver the unedited tape recordings and documents related to the Watergate Scandal, he refused to do so, claiming his "Executive Privilege".
However, the Court stated that the executive privilege had limits and it wasn't immune from judicial review, regarding the demands of due process of law, and he ought to show the evidence.