CANBERRA, Australia — Australia's prime minister said Tuesday that Parliament could legalize gay marriage this year if the nation's voters endorse it in a rare nonbinding poll in November.

Prime Minister Malcolm Turnbull said he expected the public would support marriage equality in the so-called plebiscite, and that he would personally campaign for a "yes" vote. It would be only the fourth time in Australian history, and first time in 43 years, that the government puts a legally nonbinding question to the electorate.

"I have other calls on my time as prime minister, but I will certainly support a 'yes' vote," Turnbull told reporters.

Australian Prime Minister Malcolm Turnbull speaks during a press conference at Parliament House in Canberra, Australia on Tuesday, Aug. 8, 2017. Rod McGuirk / AP

The conservative Liberal Party-led coalition was narrowly re-elected in July 2016 with a promise to let voters decide whether Australia should recognize same-sex marriage through a popular vote. But the Senate in November blocked the plebiscite, which would cost 170 million Australian dollars ($135 million) and promote a divisive public debate.

The Liberal Party held a crisis meeting late Monday to resolve infighting and rejected a push to allow lawmakers to decide the issue now.

The government on Tuesday endorsed the party decision to ask the Senate this week to reconsider allowing the plebiscite, which would be held Nov. 25. Voting would be compulsory and failure to vote would be punishable by a fine, though a voluntary vote would be held if the Senate again rejects the measure.

If most Australians want gay marriage, the Parliament would vote on legislation before the last two-week session of Parliament of the year ends on Dec. 7.

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"Strong leaders carry out their promises, weak leaders break them," Turnbull told reporters.

Supporters of same sex marriage carry banners and shout slogans as they march in Sydney on August 6, 2017. Peter Parks / AFP - Getty Images

Gay-rights advocates say enough lawmakers already back marriage equality to make same-sex marriage legal in Australia now. For the first time in Australian history, both the prime minister and opposition leader back the reform.

Rights advocates see the plebiscite as both a delaying tactic forced by a hard right-wing minority and a strategy to undermine political support.

Opponents of the plebiscite argue that the government-funded advertising campaigns for the cases for and against would give authority to bigoted and homophobic arguments. Supporters say it would give ordinary people a voice in a debate dominated by activists.

If the Senate again blocks the plebiscite, the government intends to hold a voluntary postal plebiscite by Nov. 15. Voters would mail in their opinions instead of using ballot boxes at a cost of up to AU$122 million ($97 million). Responses would be voluntary and therefore less indicative of public opinion.

Opponents argue that the postal plebiscite would also need Senate approval, and have threatened a court challenge if it proceeds. Turnbull said he is confident that the postal option did not need Senate endorsement.

Finance Minister Mathias Cormann, the government's deputy Senate leader and an opponent of same-sex marriage, said some type of plebiscite is essential if Parliament is to decide the marriage equality question.

Opposition leader Bill Shorten dismissed a plebiscite as "a colossal waste of money and time."

"Yet again the hopes of people who want to be able to marry the person they love have been dashed by a weak prime minister and the right wing of the Liberal Party," Shorten said.

"We should just get on and have a vote on marriage equality straight away in the Parliament," he added.

Lyle Shelton, managing director of the Australian Christian Lobby, said his advocacy group had collected 55,000 signatures on a petition demanding a plebiscite.

Sheldon handed the petition to Sen. Cory Bernardi, leader of the minor Australian Conservatives party, to present to the Senate. Bernardi has said he would vote against gay marriage regardless of what the plebiscite found.

Mark Moody-Basedow and his wife, Vicki, celebrated the new plebiscite plan and their second wedding anniversary by posing for photos outside Parliament House in what they described as the medieval-style outfits that they wore on their wedding day.

Vicki Moody-Basedow designed the couple's white costumes, embroidered with "righteousness," ''holiness" and "Jesus." She said they believed in "traditional marriage," but added that the majority view should prevail in Australia.

"It's the right of every Australian citizen to be able to say what they think about this topic, so I think the plebiscite is a great idea," she said.

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