Lidia Thorpe left the Greens divided – could she now do the same for the Parliament?

The Victorian senator stunned the Greens by announcing her resignation on Monday, after party leader Adam Bandt made every effort to keep her in the fold even as her denunciations of the Indigenous Voice to Parliament would have left her at odds with colleagues while serving as its Indigenous affairs spokeswoman.

After her departure, Mr Bandt on Monday night confirmed the Greens would officially back the yes campaign, saying the party had secured commitments from the government that it would proceed with truth and treaty as well as the voice.

“We want the referendum to succeed, we want First Nations justice and we want truth and treaty as well as voice,” he said.

Party insiders say that Senator Thorpe, who this year entered the chamber wearing black and with her first raised, clashed frequently with Senator Sarah Hanson-Young while her radical politics rankled other senators such as Larissa Waters and Peter Whish-Wilson.

But Senator Thorpe did have support from a group of MPs from NSW and some of the Queensland MPs elected in May after a swing towards the Greens.

She leaves the party divided and forced to argue for its own significance, after her departure reduced its numbers from 12 to 11.

“The situation remains now sort of more or less the same in the Senate,” Mr Bandt said.

Free to be me

But Senator Thorpe’s resignation statement did not seem so clear; while she intended to vote with her former colleagues on climate change, she seemed to leave the door open on other issues.

“I’m not announcing my final position on the Voice and today I want to continue my negotiations with the government,” she said.

“I will be able to speak freely on all issues from a sovereign perspective without being constrained by portfolios and agreed party positions.”

How the radical leftist acts when freed from such constraints – and what effect she may have on the finely balanced dynamics of the upper house is one of the great unknowns for the remainder of the current Parliament.

Senator Thorpe has called for an end to racial and economic inequality. But the MP who celebrated when Old Parliament House burned and has spoken at rallies calling for the police to be defunded and prisons to be abolished could be less predictable on issues soon to come before parliament such as industrial relations reform, or those farther down the road.

On the Voice to Parliament, the issue in which Prime Minister Anthony Albanese has invested so much political effort, Senator Thorpe may find common ground with those at the opposite end of the political spectrum.

Tweet from @senatorbabet

A little more than six months before her start in elected politics as a state MP for Victoria at a 2017 byelection, the future Greens senator was still staunchly opposed to the idea an Indigenous advisory body to the Parliament.

“Pauline help us stop the constitution changes,” Ms Thorpe tweeted, in a social media post uncovered by Nine last year.

“Aboriginal people say no to constitutional change.”

(Senator Hanson last year blasted her Senate colleague after she altered her Senate oath to refer to the late Queen as a coloniser).

Senator Thorpe believes the Voice would be an insult to Aboriginal sovereignty if not preceded by a treaty, or a legal agreement laying down terms between Indigenous nations and the government.

Last year she rejected as inaccurate a report that she had met former Liberal candidate Warren Mundine to discuss joining the ‘no’ campaign against the Voice.

The government does not have a majority in the Senate and has relied on the support of the Greens and one other MP to pass legislation, usually David Pocock.

It will now need two – Senator Thorpe or other crossbenchers including One Nation, Jacqui Lambie and colleague Tammy Tyrrell and the United Australia Party’s Ralph Babet – in a dynamic rich with possibilities for deal-making.

Senator Babet, who is on the political right, told The New Daily he welcomed another new independent on the crossbench, and said he could see himself working with Ms Thorpe if “she wants to team up against economy-destroying policies”.

“But the Voice is one where we both disagree [with the government],” he said.

“That’s my main issue right now.”

That would make senators Lambie and Tyrrell critical votes for the government.

On the Voice, Senator Lambie on Monday added to calls, including from Voice supporters and opponents in the Coalition, for more detail on the proposal. She also wants it to be matched with more direct investment to improve Indigenous wellbeing, including in response to a crime wave in Alice Springs.

“The PM is on notice now,” the Senator said on Monday.