[1] After being elected by the Parliamentary Liberal Party to serve as leader and prime minister, Harold Holt led the coalition to victory in the November 1966 Australian Federal Election against the Australian Labor Party opposition led by Arthur Calwell.
Holt's government introduced the Migration Act 1966, which effectively dismantled the White Australia Policy and increased access to non-European migrants, including refugees fleeing the Vietnam War.
By the end of 1967, the Liberals' initially popular support for the war in Vietnam was causing increasing public protest.
[3] On 17 December 1967, Holt disappeared in heavy surf while swimming off Cheviot Beach, near Melbourne, becoming the third Australian prime minister to die in office.
[5] McEwen ruled out maintaining the coalition if deputy liberal leader William McMahon became prime minister.