In the u. s supreme court case, u. s.v. nixion, what constitutional princple was the focus of the ruling.

A grand jury returned indictments against seven of President Richard Nixon's closest aides in the Watergate affair. The special prosecutor appointed by Nixon and the defendants sought audio tapes of conversations recorded by Nixon in the Oval Office. Nixon asserted that he was immune from the subpoena claiming "executive privilege," which is the right to withhold information from other government branches to preserve confidential communications within the executive branch or to secure the national interest. Decided together with Nixon v. United States.