President Richard Nixon Visits the Shah of Iran - 1972

While Eisenhower was incapacitated, Nixon was called on to chair several cabinet sessions and National Security Council meetings, though real power lay in a close circle of Eisenhower advisers, from which Nixon had always been excluded. After his stroke, Eisenhower formalized an agreement with Nixon on the powers and responsibilities of the vice president in the event of presidential disability; the agreement was accepted by later administrations until the adoption of the Twenty-fifth Amendment to the U.S. Constitution in 1967.