Lyndon Baines Johnson (; August 27, 1908 – January 22, 1973), often referred to by his initials LBJ, was an American politician who served as the 36th president of the United States from 1963 to 1969, and previously as 37th vice president from 1961 to 1963. He assumed the presidency following the assassination of President John F. Kennedy. The following year, Johnson won in a landslide, defeating Senator Barry Goldwater of Arizona. With 61.1 percent of the popular vote, Johnson won the largest share of the popular vote of any candidate since the largely uncontested 1820 election.