The vote by party lawmakers, scheduled for Monday, is an effort by Gillard to knock down a power struggle that has been percolating for weeks, and that spilled over on to the world stage yesterday when Rudd resigned as foreign minister during an official trip to the US. The fight could lead to the collapse of the government and early elections.
In Washington, Rudd would not say whether he will challenge Gillard in the leadership ballot, telling reporters he would announce that decision when he returns to Australia on Friday. But he said he believes the Labor Party will lose national elections scheduled for next year if Gillard remains its leader.
Gillard said she will abandon her leadership ambitions if Labor lawmakers choose Rudd over her on Monday, and she called on Rudd to do the same if he loses.
"We need a leadership ballot to settle this question once and for all," she told reporters in Canberra, the capital.
Analysts expect that Gillard has enough support in the House of Representatives to remain in power for now, but she and her government are unpopular among voters. And Rudd supporters said that even if he lost Monday, he would simply build support and try again later.
A Rudd supporter, Sen. Doug Cameron, said a Monday poll would be unfair because Rudd would not have time to canvass support.
"It's clear that some senior ministers are intent on putting a stake through Kevin Rudd's heart and I don't think that's justified," Cameron told Australian Broadcasting Corp. television.
For weeks, Rudd denied widespread rumors that he was planning a run for Gillard's job. Before Rudd announced his resignation, Gillard had refused to comment on media reports that she intended to fire him as foreign minister for disloyalty.
Rudd accused Gillard of showing disloyalty to him by failing to silence senior ministers who accused him of being dysfunctional and of secretly undermining the Australian government while he served as its top international envoy.
As Rudd turned from Cabinet member to rival, Gillard criticized his performance as prime minister, and her supporters have been warning about his notorious temper. Gillard supporters have been accused of leaking a video to media over the weekend in which Rudd, then prime minister, became enraged as he struggled with the words in a Chinese-language speech.
Nick Economou, a political scientist at Monarch University, said Rudd's resignation caught Gillard wrong-footed.
"Everyone can figure out the thing to do is to jump before you're pushed. That way you've got the high moral ground instead of being sent to the back bench as the product of the prime minister's authority," Economou said.
He called Rudd's resignation "an absolute strategic disaster" for Gillard that made the Australian government appear dysfunctional in the capital city of the United States, Australia's most important security partner.
The political crisis may already have had broader effects: Some economists blame it for a slump in the Australian dollar, which fell to its lowest level in a month Thursday.
"I think markets are worried about a potential leadership change, what it means for any policy measures they have for Australia and the uncertainty it provides," Kathy Lien, director of currency research at brokerage GFT Forex, said from New York.
The government could fall if Rudd wins because Labor's single-seat majority in the House depends on a coalition with two independent lawmakers and one from the Greens Party. Early elections would be held if neither Labor nor the conservative opposition coalition can muster a majority.
One of the independents in the Labor coalition, Tony Windsor, warned that he could bolt if Rudd returns to power. "If that was the scenario, maybe it's time the people had their say in terms of who can govern," Windsor told ABC.
Rudd said his supporters regard him as the best prospect to lead the ruling party to victory in the next elections and "to save the country from the ravages of an Abbott government," referring to the current opposition leader, Tony Abbott.
Gillard ousted Rudd as prime minister in June 2010 in an internal coup, and their centre-left Labor Party scraped through elections later that year to lead a minority government.
Rudd suggested that whatever Gillard's fate is, it will be fairer than his own in 2010. "I can promise you this: There is no way - no way - that I will ever be party to a stealth attack on a sitting prime minister elected by the people," he said. "We all know that what happened then was wrong and it must never happen again."
Gillard on Thursday gave her most scathing explanation yet of why she had challenged Rudd after four years as his deputy. She said while Rudd was an "excellent campaigner," he "struggled" to lead.
"I determined to contest the prime ministership in circumstances where the government that Kevin Rudd had led had entered a period of paralysis," she told reporters.
"Kevin Rudd as prime minister always had very difficult and very chaotic work patterns," she added.
Many Australians were angry when the government dumped Rudd, who was swept into office as prime minister by general elections in 2007. In Australia's system, the prime minister is chosen by a majority of lawmakers in the House of Representatives, not by voters.
Opposition leader Abbott said Rudd's resignation confirmed that the government is unworthy to continue in office, and that Gillard had no authority to govern because she lost Labor's majority in the House of Representatives in the 2010 election.
"I don't always agree with Kevin Rudd. I thought Kevin Rudd was a poor prime minister. But at least he had this virtue: He was the last Australian prime minister to have a mandate from the people," Abbott said.
