Australian government dumps PM Gillard for former leader Rudd By James Grubel CANBERRA (Reuters) - Australia's ruling Labor Party elected former leader Kevin Rudd as prime minister and dumped Julia Gillard on Wednesday, in a dramatic move to try and head off a catastrophic defeat at elections due within three months. The return of Rudd could now see Australia go to an election in August rather than the set date of September 14, to cash in on his greater popularity with voters and an expected honeymoon period with the electorate. Rudd, a former diplomat who speaks Mandarin, won a Labor Party ballot with 57 votes to Gillard's 45. Gillard promised to quit politics if she lost the ballot. The leadership change followed a series of opinion polls showing Gillard's minority government could lose up to 35 seats at the looming elections, giving the conservative opposition a massive majority in the 150-member parliament. But polls also show Rudd is more popular with voters and his return to the prime ministership, which he lost to Gillard in June 2010, could stem the size of Labor's election loss. The shift from Gillard to Rudd is unlikely to have any major policy implications, as both are strong supporters of Australia's military alliance with the United States and strong supporters of growing ties with top trading partner China. Gillard has struggled to win public support despite ongoing economic growth and low unemployment and low interest rates at a time when other developed countries are struggling to keep out of recession. Gillard has also pushed social reforms that pour money into schools, and which help disabled people gain access to much-needed free care, but the changes have done little to shift her dwindling support in opinion polls. Voters have also remained angry that her government, which holds a one-seat majority with support from the Greens and a clutch of independents, introduced a controversial carbon tax in a backflip from her 2010 election promise not to do so. Several key ministers, including Treasurer Wayne Swan and Communications Minister Stephen Conroy, have said they would not serve under Rudd. Rudd said he would hold no grudges against internal critics who have openly slammed his previous stint as prime minister, and said he would not punish ministers who have remained stubbornly loyal to Gillard. If I win this ballot, every effort I have in my being will be dedicated to uniting the Australian Labor Party. No retributions, no paybacks, none of that stuff. It's pointless, it's old politics," Rudd said ahead of the vote. Editing by Clarence Fernandez