 The incumbent Liberal–Country coalition led by Prime Minister Robert Menzies defeated the opposition Labor Party led by H. V. Evatt, despite losing the two-party preferred vote.This was the first federal election that future Prime Minister Gough Whitlam contested as a member of parliament, having entered parliament at the 1952 Werriwa by-election.The election was complicated by the Petrov Affair, in which Vladimir Petrov, an attache to the Soviet embassy in Canberra, defected amidst a storm of publicity, claiming that there were Soviet spy rings within Australia.