The privilege extended to the executive branch to withhold certain information from Congress or the courts. The need to withhold may be to preserve the confidentiality of communications within the executive, or to serve the national interest.

Throughout U.S. history, presidents have invoked executive privilege, although the concept is not explicitly stated in the constitution. The privilege was restricted by the Supreme Court in 1974, after President Richard Nixon invoked it in the Watergate scandal. The Court ruled that executive privilege could not be applied to prevent evidence being supplied in a criminal case. In 1998, President Bill Clinton invoked executive privilege in an attempt to prevent his aides testifying before a grand jury in a criminal inquiry. As in 1974, the courts ruled that executive privilege must give way to the needs of a criminal case. The administration of President George W. Bush (2001-2009) invoked executive privilege on many occasions.