The President began the trip by going to the memorial service for Australian Prime Minister Harold Holt, who had disappeared in a swimming accident and was presumed drowned. The White House did not reveal in advance to the press that the President would make the first round-the-world presidential trip. The trip was twenty-six thousand nine hundred fifty-nine miles (43,386.3 km) completed in only 112.5 hours (4.7 days). Air Force One crossed the equator twice, stopped at Travis Air Force Base, in Honolulu, Pago Pago, Canberra, Melbourne, Vietnam, Karachi, and Rome.

1968 presidential election
Main article: 1968 United States presidential election
President Johnson meets with Republican candidate Richard Nixon in the White House, July 1968.
As he had served less than 24 months of President Kennedy's term, Johnson was constitutionally permitted to run for a second full term in the 1968 presidential election under the provisions of the 22nd Amendment.[267][268]
Initially, no prominent Democratic candidate was prepared to run against a sitting president of the Democratic Party. Only Senator Eugene McCarthy of Minnesota challenged Johnson as an anti-war candidate in the New Hampshire primary, hoping to pressure the Democrats to oppose the Vietnam War. 