Jacqui Lambie plays the Harradine game

In an intervention that would resonate with the late Brian Harradine, who was legendary for extracting concessions for Tasmania in return for his Senate vote, Jacqui Lambie has demanded the federal government forgive the state’s housing debt.

The Tasmanian senator – who has returned to the parliament after being disqualified in the citizenship crisis – is the last vital vote if the government is to rely on the crossbench, rather than Labor, to pass its tax package intact on Thursday.

Lambie refused to be drawn publicly until this week, although she’s had plenty of attention. For example the two Centre Alliance senators, Stirling Griff and Rex Patrick, journeyed to Davonport to see her. She and they agreed to keep in touch as issues came up.

In the last couple of days, sources have been sure Lambie was in the government’s tax cart.

But on the eve of the vote, she issued a strong statement and video, saying she had “yet to arrive at a final position”. (She supports the first and second stage of the package but is arguing over the final one, delivered years on.)

She condemned homelessness in Tasmania, linking it to the $157 million the state owes the federal government in social housing debt (involving payments of some $15 million a year).

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These debts are from funds borrowed by the states and territories from the federal government between 1945 and 1989 to build new housing, maintain existing stock and provide housing assistance.

“Tasmania is paying 50c in every dollar of our state housing budget back to the federal government in interest and debt repayments. That means we are building half as many homes, helping half as many people,” Lambie said.

“This debt is holding Tasmania back and denying shelter to thousands of Tasmanian families. The Commonwealth coffers don’t need $15 million a year from the Tasmanian budget,” she said.

“It’s only by having the balance of power for Tasmania in the Senate that real debt relief is going to happen and that’s what I am here to fight for.

"There is no way in good conscience I can vote for substantial tax cuts without making sure that the people who so desperately need a roof over their heads aren’t left to go without.”

The Tasmanian Liberal government has been pressing the federal government to forgive the debt, although Tasmanian Liberal senator Eric Abetz has opposed that, saying it would lead to demands from other states.

The Morrison government has claimed it won’t do any deals in its push to get the tax package through. In fact, this has not been true – Centre Alliance is confident, following detailed negotiations, there will be measures on gas policy to help smooth the way for its votes.

But Lambie’s demand is a very direct quid pro quo.

Senate leader Mathias Cormann, the government’s negotiator on the tax package, declared on Wednesday: “We are always happy to engage with senators in relation to issues of concern to them and their constituents”.

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There is a general expectation the tax package with its three stages intact will be passed this week. It’s just a matter of who is blinking.

Does the government throw some money at Lambie, not just to secure her support on this measure but to keep her on side for the future?

Would Lambie retreat from her stand if she was not accommodated and still vote with the government on the package - or would she have a long-lasting hissy fit?

According to some sources, a fix was likely already in with Lambie on Wednesday.

Anyway, Labor is there as a fallback. Despite its objections to stage three, it can’t afford to be endlessly blamed for blocking tax relief.

Regardless, it was clear that every which way Pauline Hanson’s One Nation had been left out in the cold.