In the case, in which Nixon was accused of being involved in the Watergate Scandal (1972), the Supreme Court ordered him to deliver the unedited tape recordings and documents related to the Watergate Scandal. However, the President refused to do so, claiming his "Executive Privilege", that is to say, his right as President to withhold information from other government branches to preserve confidential communications within the executive branch or to secure the national interest.
Nevertheless, 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.