The run-up to the 1968 election was transformed in 1967 when Minnesota’s Democratic senator, Eugene J. McCarthy, challenged Democratic Pres. Lyndon B. Johnson on his Vietnam War policies. Johnson had succeeded to the presidency in 1963, following the assassination of John F. Kennedy, and had been overwhelmingly reelected in 1964. Early in his term he was immensely popular, but U.S. involvement in Vietnam, which had escalated invisibly during the presidential administrations of both Dwight D. Eisenhower and Kennedy, became highly visible with rapidly increasing U.S. death tolls, and, as the war’s unpopularity mounted, so did Johnson’s.