Executive privilege is the constitutional doctrine that allows the U.S. president and executive branch officials to keep certain communications confidential to protect governmental functions. Though it is not explicitly written in the Constitution, the Supreme Court affirmed its legitimacy in United States v. Nixon (1974), ruling it is a qualified privilege rooted in the separation of powers. The doctrine is divided into two types: the presidential communications privilege, which applies to the president's immediate advisors and is harder to overcome, and the deliberative process privilege, which is based on common law and can extend further down the chain of command. A key precedent was set in 1796, when George Washington refused to give the House of Representatives documents about the Jay Treaty, but provided them to the Senate, which holds treaty ratification power. Historically, presidents, Congress, and the courts have avoided open confrontations through compromise, leaving the scope of the privilege in most congressional disputes largely untested in the Supreme Court.