Saturday’s Aston by-election is shaping as a topsy-turvy affair – could it upend the Liberal leadership of Peter Dutton and a century of political history? Or could it prove he is immune to normal political consequences?

Officially the ALP has campaigned hard in the outer Melbourne seat, only in the expectation it will be dealt a noble loss in keeping with historical trends.

By-elections do not favour governments. The last time a government took a seat off the opposition in one was in 1920 and in the past 35 years by-elections have produced an average swing of 5.1 per cent against the government of the day.

But one Labor source told TND a poll in Aston had shown a swing towards the government – a finding that has buoyed the party.

That is denied by senior figures in the ALP campaign – and that is why some Liberals are so worried.

A Labor win?

The source would not be drawn on the actual polling figures, or the usual measures included when such research is published.

But, in a seat hanging on a margin of 2.8 per cent, even a slender swing would mean the by-election starts as an ultra-marginal contest – with a once-in-a-century event not entirely inconceivable from there.

How much is anyone on the ground drawing from these conclusions? It depends.

“The polling commissioned has not been extensive enough for us to know,” a senior Labor figure said, pouring cold water on TND‘s queries.

A senior Liberal MP offered this rejoinder: “Bulls–t”.

Recent visits to the electorate by Prime Minister Anthony Albanese – including this week with his Skills and Training (including TAFE) Minister Brendan O’Connor and Early Childhood Minister Anne Aly – showed Labor was playing to win and not skimping on research, the seasoned campaigner reckoned.

But it was only last November that state election polling seemed to get things badly wrong in Victoria – predicting a close vote when Premier Daniel Andrews’ state Labor Party was instead returned with a thumping majority.

Some Liberals make an extraordinary concession about their anxiety and are talking down Labor’s chances, even if their ultimate goal on Saturday is beating expectations.

“It’s about local issues and road-funding cuts. No one is hearing anything about Labor [being rewarded] by voters,” one federal MP said.

Cost-of-living is the main issue for voters, as in last weekend’s NSW election – but not in the usual way that prompts anti-government anger. Labor has made the issue the centre of its own campaign, which advertises a coming discount to TAFE and childcare that is now just a couple of months away.

“It’s a very unusual by-election,” agreed veteran campaign pollster John Utting.

He noted that Mr Dutton’s recent media appearances in Aston – in contrast to less progressive NSW, where the state Coalition government placed him in protective custody – lacked the commanding air of a leader on the hustings.

“Vote for the [local MP…] and get Peter Dutton,” a mobile Labor attack billboard at last week’s NSW election read.

Mr Dutton was presented as a sinister and diminished bogeyman leaning out from a pure black backdrop.

Such messaging has kept Labor ahead in the seat of Ryde (Chinese ancestry 19 per cent) and on the same turf as Bennelong, one of the seats where Mr Dutton’s comments about “preparing for war” were rejected by Chinese voters at last May’s federal poll.

In Aston, where there are twice as many people of Chinese descent (15 per cent) as the Victorian average and advertising is not so limited, the government will test whether Mr Dutton’s image has changed since he was defence minister.

Mr Utting said campaigns were sometimes like the mystery that Sherlock Holmes solved by noticing the dog that didn’t bark.

Mr Dutton, the government has alleged in question time recently, is  keeping a low profile while otherwise doing as little as is needed to avoid claims there are large parts of Australia where he is seriously unpopular (a potential long-term hurdle in his line of work).

The Labor caucus heard on Tuesday that Mr Dutton had been “in hiding” and, if he secures anything less than the median 5 per cent swing toward him on Saturday, he will have failed.

One almost suspects Mr Albanese may be setting up his opposite number for failure of historic proportions with this choice of benchmark.

Mr Dutton has made a show of not reacting in Parliament and has sat placidly in Question Time this week as the government takes questions about the by-election with growing zeal.

‘Who else?’

One Liberal MP not thought to be in Mr Dutton’s core group of supporters said his leadership would roll on completely unaffected by whatever happened in Aston.

“He’s rock solid,” they said. “Who else is there?”

Some of the only credible options with any name recognition are women in the upper house.

(To have the Liberal Party’s leader serving in the Senate would be a break with convention but the office of opposition leader is in its own way a newfangled addition first recognised in parliament in 1920).

Mr Utting said there was no escaping what a loss would mean when the Victorian Liberals are engulfed in scandal, the NSW electorate has thrown out the Coalition and official interest rates are at recent records.

“There’s always no alternative until there is one,” he said.

Other Liberals told TND they were pessimistic but expected to limp over the line in the face of attacks on candidate Roshena Campbell, who is a whip-smart newspaper columnist but who files from Brunswick. She’s a barrister too.

Labor’s Mary Doyle lives next door to the electorate but has a familiar local story as a cancer survivor and previous candidate.

The ultimate question is how much did the 11-point primary swing the Coalition withstood in May leave for a further rejection, Liberals reckon.

“Was it Scott [Morrison]? Was it women? Was it integrity?” the Liberal MP queried.

“We took a big hit and it’s a question of how far from that we are in voters’ minds.”