In December 1973, two months after the resignation of Spiro Agnew, Ford became the first person appointed to the vice presidency under the terms of the 25th Amendment by President Richard Nixon. After the subsequent resignation of President Nixon in August 1974, Ford immediately assumed the presidency. His 895 day-long presidency is the shortest in U.S. history for any president who did not die in office. As president, Ford signed the Helsinki Accords, which marked a move toward détente in the Cold War. With the collapse of South Vietnam nine months into his presidency, U.S. involvement in Vietnam essentially ended. His 895 day-long presidency is the shortest in U.S. history for any president who did not die in office. As president, Ford signed the Helsinki Accords, which marked a move toward détente in the Cold War. With the collapse of South Vietnam nine months into his presidency, U.S. involvement in Vietnam essentially ended.