The same-sex marriage plebiscite is the political fix that is destroying the Turnbull government. A huge claim, but consider this: just as John Howard’s stubborn refusal to say “sorry” to the Stolen Generations of Indigenous children defined his late career loss of touch, so too is this farce defining Malcolm Turnbull.

As an issue it is not the whole story behind this week’s shock Newspoll result that saw Labor take a clear lead in the two-party preferred, 52 to 48. But it is as sure an indication as any that the barely re-elected government has not been impressing voters since its return to power. More damaging is the downward spiral that is Turnbull’s approval.

Just last week the Liberals’ campaign director, Tony Nutt, told us Turnbull’s standing was critical to the Coalition coming from behind in internal polling to fall across the line in July. Turnbull is still preferred as prime minister but he is now less popular than Bill Shorten. Shorten’s stocks have been climbing out of the cellar while Turnbull’s are heading there at an alarming rate. Turnbull’s approval is now a net negative 23, 61 points down on his peak in November.

Brandis appealed to Shorten’s “better angels” to “stop playing politics with gay people’s lives”.

Of course, opinion polls don’t predict the future; but they do give us a snapshot of the present. This is a point Turnbull made back in 2012. On Channel Ten’s now defunct Breakfast show he was asked to explain how the Coalition could stick with the very unpopular Tony Abbott, even though it was ahead of the Gillard government in Newspoll. Wasn’t Abbott at risk of taking the party down with him? Turnbull’s answer: “Between elections the litmus test is the party vote in the opinion polls and we’re well ahead on that score. On that basis, he’s doing a very good job.”

Well, on both those scores Turnbull is failing. The challenge now is to ensure this poll is not the first in a series. It will be a daunting task. In responding to the poll, Shorten took a leaf straight out of Abbott’s opposition leader playbook. “I don’t need an opinion poll … to be told that Malcolm Turnbull is out of touch ... To be told that his policies of cutting Medicare, a hit list on schools, not properly funding childcare, not standing up for Australian blue-collar jobs – I don’t need an opinion poll to tell me he’s taking Australia down the wrong path.”

No mention of the plebiscite there. But wait, there’s more, a lot more. To hammer home his theme on “saving blue-collar jobs”, Shorten has visited four OneSteel Arrium sites in three states. The company, he says, needs a grant of $50 million to upgrade its technology and save 7000 jobs. His message: “Mr Turnbull could help fund the $50 million by not going ahead with the expensive, unnecessary, $200 million government taxpayer-funded opinion poll on marriage equality.”

The Newspoll shock on Tuesday was followed by another even bigger one on Wednesday. It found 48 per cent of Australians would prefer to have politicians in parliament decide, 39 per cent back the plebiscite and only 13 per cent are undecided.

There are two huge factors undermining the “people’s vote”. Shorten has been assiduous in prosecuting them. A Galaxy poll in July found that support for the plebiscite fell to 35 per cent when people were told the poll was non-binding on politicians. It plummeted to 25 per cent when told of the cost. Back then, it was put at $160 million. That was before cabinet added another $15 million for “Yes” and “No” case advertising. The bill tabled on the last day parliament sat revealed an extra $32 million to set up the vote.

Labor and Liberal politicians are finding people are fed up with the argument and just want it dealt with. The quickest, cheapest and safest way, as Labor, the Greens, Nick Xenophon and others say, is for “parliamentarians to do their job”. But there is no way opponents of same-sex marriage want that to happen.

Last Monday, one of the staunchest “No” men in parliament, the Nationals’ George Christensen, made this clear as he worked in his Queensland electorate based around Mackay. He was somewhat bemused by reports that Attorney-General George Brandis had invited to Brisbane his shadow, Labor’s Mark Dreyfus, and equality spokesperson Terri Butler. The media was carrying reports of compromise in the air, such as dropping the public funding or making the plebiscite binding on politicians. One option: parliament passing a same-sex marriage bill that would be immediately triggered if the “Yes” vote succeeded.

On the front page of The Courier-Mail, Nationals leader Barnaby Joyce ruled out any compromise. Uncharacteristically, Christensen wasn’t in complete agreement with his leader. He told The Saturday Paper that if Brandis proposed a binding vote for politicians, he wouldn’t mind. Clearly he appreciates the enormous damage Liberal “No” voters – people such as Eric Abetz, Andrew Hastie and Cory Bernardi – have done by saying they would not be bound by a “Yes” vote but would vote according to their consciences. A free vote for them and no one else. They have given Shorten one of his most potent lines, repeated at every news conference in the parliamentary recess.

“What is the case to spend $200 million of taxpayer money on an opinion poll which Mr Turnbull can’t even make members of his own party agree to?” Shorten asks. “Mr Turnbull is saying to Australians, it will be compulsory for 15 million people to vote on same-sex marriage, to vote on marriage equality ... If they don’t vote, they will be fined. But it’s not compulsory upon Liberal Party MPs to accept the result? That is a sick joke.”

If the plebiscite is voted down in the parliament, as is certain – Shorten will recommend this course to caucus – Turnbull will be left in a world of even more pain. Christensen says the only option is a plebiscite. If the prime minister accepts this in the hope the issue will go away, he is deluding himself. Labor, the Greens and several independents in both houses have private member’s bills. The gag may work in the house of representatives, but the more often it is applied, the less credible will be Turnbull’s claim that it is Shorten who is standing in the way of marriage equality. In the meantime, the senate has the numbers to pass such a bill and will certainly try.

In the end Christensen needn’t have worried. The attorney-general put no compromise on the table. A curious tactic from the minister charged with getting the plebiscite legislation through parliament. Labor insisted in the meeting that its position was for a parliamentary vote as soon as parliament resumes. The meeting had all the appearances of a charade.

George Brandis appealed to Shorten’s “better angels” to “stop playing politics with gay people’s lives”. The Newspoll, like the Essential one the week before, shows Australians have had enough of the games and want a parliamentary free vote. Shouldn’t be too hard for the Liberals. We have been told for decades such a vote is in the DNA of the party, unlike the straitjacket Labor MPs have to endure, forbidden as they are from crossing the floor.

Labor says its research shows that while voters still have a grudging admiration for Turnbull, they have formed the view that he “stuffs things up”. His inability to deliver on his election promise of a plebiscite shows he has been outgunned by Shorten. Or is it that the government’s own disarray has played into Labor’s hands?

The broader political context of the same-sex marriage imbroglio is the imperative of budget repair. That gives added credibility to Shorten’s wrong spending priorities attacks. Especially as the government’s touch in the scramble for revenue is just as cack-handed.

Joe Hockey’s decision in the 2015 budget to hit backpackers with a 32 per cent tax from the first dollar they earned was a political time bomb that is still ticking. The motivation for the Hockey cash grab, carried without demur by Scott Morrison’s 2016 budget, was the desperate scrape for extra revenue. Already hamstrung by vested interest in the business community and their own wealthier constituency, there weren’t a lot of options.

In announcing he would cut the rate to 19 per cent, Morrison said the reason for the tax was to close a loophole opened when Labor’s treasurer Wayne Swan raised the tax-free threshold to $18,000. Loophole? He must be joking. Before the Hockey move, suggested by Treasury, backpackers were treated like anyone else who earns a buck in Australia. The too-clever-by-half thinking was: hit the foreign workers because they are not voters. This forgot about the labour force impact on agriculture and tourism. It has been immediate and damaging. Tonnes of produce will be left to rot this summer for want of seasonal workers. Already the message has travelled around the world via social media that the trip to Australia is just not worth it.

Nick Xenophon says it’s a shemozzle. Labor is unlikely to support it in its current form. Ironically, George Christensen is happy after previously threatening to quit the Nationals over it.

It sure looks like a government struggling to find its mojo.