The United Australia Party held a leadership election on 18 April 1939, following the death in office of Prime Minister Joseph Lyons on 7 April. Robert Menzies narrowly defeated Billy Hughes – a former Nationalist prime minister – on the third ballot, following the earlier elimination of Treasurer Richard Casey and Trade Minister Thomas White. Another former prime minister, Stanley Bruce, had also been considered a leadership contender, but for various reasons (including his position outside of parliament as High Commissioner to the United Kingdom) he was never nominated. Menzies was not sworn in as prime minister until 26 April.