Since 1968 only two deputy prime ministers have gone on to become prime minister: Paul Keating and Julia Gillard. In both cases, they succeeded incumbent prime ministers who lost the support of their party caucus mid-term and their election as party leader preceded their predecessor's resignations and their subsequent appointments as prime minister. Frank Forde, who had been deputy Labor leader when John Curtin died, was interim prime minister between 6 and 13 July 1945, when a leadership ballot took place that elected Ben Chifley as Curtin's successor.