The government’s same-sex marriage plebiscite bill has been voted down in the Senate, with no last-minute deal emerging to save the non-binding poll.

On Monday evening Labor, the Greens, Nick Xenophon Team and senator Derryn Hinch combined in the Senate to block the plebiscite by 33 votes to 29, as they had promised weeks before.

Labor leader in the Senate, Penny Wong, used the debate on Monday to take aim at the prime minister, Malcolm Turnbull, saying the opposition did not trust him to stand up to prejudice.

On Monday afternoon, NXT senator Stirling Griff told the Senate that LGBTI people do not deserve to be vilified or “treated differently”.

“It is not my role nor the role of any other person in this place to tell a person their relationship does not warrant equality before the law,” he said.

Griff confirmed the NXT’s three senators would oppose the plebiscite because “a far less harmful, far less costly alternative exists” – a free vote in parliament.

“We’re elected to make decisions not to outsource them,” he said.

The Liberal senator Dean Smith said he opposed the vote because he was a constitutional conservative and regarded it as “an abdication of parliament’s responsibilities”.

Smith said a popular vote would “irretrievably undermine the principle of parliamentary sovereignty” and “once undermined there is no telling where it will end up”.

He said parliament should not expose future generations to the risk of a precedent that could lead to popular votes determining “freedom of speech and freedom of worship or on whether or not Australia accepts immigrants from a particular nation”.

Wong told the Senate that Labor opposed the plebiscite because “we did not want our families and our children publicly denigrated”.

She said that those opposed to same-sex marriage “will stoop to any argument to prevent change”.

Listing Labor’s objections, she added: “Because we do not trust this prime minister and this government to stand up for us, our children and for our community.

“Because we have seen their silence when their own backbench speak. Because we know their weakness in the face of prejudice.”



Wong reiterated remarks in the Lionel Murphy lecture in which she argued Australia did not hold plebiscites on other fundamental issues of justice and human rights.

Brandis used his speech to claim that Labor leader Bill Shorten could not have a principled objection to the plebiscite because he had said in 2013 he was “relaxed” about the prospect of one. Similarly, Greens leader Richard di Natale had previously backed the idea, he argued.

Brandis credited Smith as voicing the only sensible argument against the plebiscite, but repeated his frequent argument that a plebiscite would not set a bad precedent because - unlike other issues - Australians all have an “equal stake” in marriage and the political class had no greater wisdom into its definition.

The attorney general asked if Labor and others were opposed to harmful debate why they didn’t seize the plebiscite as a means to resolve the issue in months not years.

The Greens LGBTI spokeswoman, Janet Rice, said that far from providing a path to marriage equality, a plebiscite represented an “unnecessary detour ... through difficult terrain”.

“It is at least insensitive to the LGBT community … and at best, it will result in divisive hurtful campaigning with no guarantee of progressing marriage equality.”

Rice spoke of her marriage to her transgender partner, Penny Whetton, noting she would not have been able marry her if Penny had transitioned sex earlier in her life.

The Liberal senator Chris Back spoke in favour of a plebiscite, arguing the government had taken the policy to the July election.

Back claimed he was the first to propose a plebiscite in the Coalition party room in August 2015, a policy that was opposed by Turnbull at the time but then accepted as government policy when he took over as prime minister in September.

Independent Jacqui Lambie said she supported a plebiscite to test the will and conscience of the Australian people.

If the bill is defeated as expected, attention will turn to whether Turnbull will advocate or allow a free vote on same-sex marriage, which he has not ruled out, or whether the government will maintain its policy for a plebiscite, as conservatives in the Coalition have demanded.

There are two same-sex marriage bills currently in the lower house: one from Labor and one from a cross-party group.

Labor’s equality spokeswoman, Terri Butler, told Guardian Australia Labor would join the cross-party bill if a Coalition MP joined. But Coalition MPs have steadfastly maintained there is no “plan B” if the plebiscite bill is defeated and said marriage equality could be delayed for years.

Labor, the Greens and others in favour of same-sex marriage may also introduce a Senate bill to increase pressure for a free vote.

Australian Marriage Equality has developed the Equality Campaign to demonstrate the strong and diverse support for marriage equality.

On Monday LGBTI rights group Just Equal presented Rice with a petition of 90,000 signatures calling for a free vote on same-sex marriage.

Just Equal is continuing its work with the Make It Law campaign and has supported a crowdfunding campaign by Parents and Friends of Lesbian and Gays Australia.