A prominent independent candidate is threatening to spoil the Morrison government’s one-seat majority.
Voters will head to the polls in the Sydney harbourside electorate of Wentworth this weekend.
The campaign has been unusually fierce in the affluent seat, which is normally considered an extremely safe Liberal stronghold.
Political operatives are knocking on doors. The Liberals brought party elder John Howard to the electorate this week so he could soothe traditional supporters who were “grumpy” at the dumping of their former member and former prime minister Malcolm Turnbull.
The Liberals are running Dave Sharma, a former ambassador to Israel. Mr Sharma has an impressive resume. He arrived in Australia as a migrant from Canada with Indian heritage, graduated from high school with a score of 100, and quickly rose through the diplomatic ranks to become Australia's youngest ever ambassador.
But independent candidate Kerryn Phelps has emerged as the most likely threat. The local doctor and Sydney city councillor is a social progressive who campaigned on same-sex marriage and advocates tougher action on climate change.
On Friday, Prime Minister Scott Morrison said he expected his candidate to lose.
Asked by a journalist if Mr Sharma was likely to be defeated, on balance, Mr Morrison responded: "I've been saying that for the last couple of weeks."
"I think the expectations are clearly set in this direction," he said.
Who lives in Wentworth?
Wentworth is an unusual seat. It is extremely wealthy, per capita, and highly educated. The electorate tends to prefer socially progressive Liberals like Mr Turnbull, which explains Dr Phelps' attacks on the conservative 'hijacking' of the party.
Census data from 2016 shows “no religion” was the most common response to the religion question in Wentworth, at 33 per cent. But 20 per cent of residents identify as Catholic, while 12.5 per cent identify as Jewish.
Who else is running?
Labor candidate Tim Murray is the third major contender, with polls suggesting he could attract a similar primary vote to Dr Phelps.
The Australian voting system means Dr Phelps will need to get to at least second place on first-preference votes to have a chance. If she does, she will likely benefit from Mr Murray's preferences and those from the other independents in the race.
Greens candidate Dominic Wy Kanak, who is hoping to make a difference as an Indigenous MP, has also participated in Wentworth debates. There are 16 candidates in total.
Why one seat matters
Wentworth matters because the Morrison government only has a one-seat majority in the House of Representatives.
Mr Turnbull won the seat on a convincing 68 per cent over Labor at the last election, but polls suggest the swing against the government could be enough to put the seat in doubt this time.
That does not mean an independent victory will bring down the government though. The Coalition can hang on to power, but it would rely on a group of crossbench independents in the Lower House to guarantee confidence in the government and supply the flow of money.
The existing crossbenchers would see their stocks rise substantially if they gained new power to influence government policy.
Dr Phelps says she doesn’t want to bring down the government, but she’s not going to sign off on bills she fundamentally disagrees with, citing the government’s likely introduction of a Religious Discrimination Act.
The others on the bench see an opportunity.
Crossbenchers Rebekah Sharkie and Andrew Wilkie have already signalled a move to bring asylum seeker children and their families from Nauru to Australia for medical attention. Mr Wilkie said he was hopeful Dr Phelps would give them the numbers to pass the bill as early as next week.
Queensland crossbencher Bob Katter has made it clear he will cause “mayhem” for the Morrison government unless it heeds his demands for a longer, tougher Royal Commission into the banks and investment in dams.
The Liberals are hoping the prospect of further instability in the parliament will discourage Wentworth voters from voting in protest.
“Don’t risk a hung parliament,” the government says.
The embassy controversy
In the week before the by-election, Mr Morrison unveiled he would “consider” moving Australia’s diplomatic outpost in Israel from Tel Aviv to Jerusalem. He would also consider pulling out of the Iran nuclear deal, he said.
Both are moves that US President Donald Trump has already made.
The Israelis welcomed it, while the Palestinian Authority warned the move would further inflame tensions and threaten peace negotiations. It also prompted warnings from Indonesia and sparked reports it could endanger an all-but-secured trade deal with the Islamic-majority Asian nation.
Social media company Meltwater has analysed social media chatter in the lead-up to the by-election using artificial intelligence.
The company found the Jerusalem debate was the focus of discussion about Mr Sharma – a former ambassador to Israel.
Some, including the Labor opposition, claimed the timing of the announcement was an attempt to win votes from Wentworth's Jewish residents.
The email scandal
In the same week, a hoax email was sent to hundreds of voters in Wentworth that falsely claimed Dr Phelps had been diagnosed with HIV and was therefore pulling out of the race, directing her followers to support Mr Sharma instead.
Its origins are still unknown but the Liberal Party has denied involvement, and Dr Phelps has accepted the denial. Mr Sharma joined a chorus of voices in condemning the email.
Meltwater’s social media analysis shows chatter about Dr Phelps spiked in the wake of the scandal, rivalling Mr Sharma for the total number of mentions.
“The smear campaign that has apparently taken place is really generating a lot more coverage for Kerryn Phelps. Whether any coverage is a good thing or a bad thing, that's too hard for Meltwater to be able to tell,” the firm’s area director Cimon Constantine told SBS News.
What do the polls say?
Recently leaked internal Liberal party polling put Dr Phelps ahead of Mr Sharma, 55-45 on two-party preferred.
But as some commentators have pointed out, it could be in the Liberals’ interests to downplay their chances of holding the blue-ribbon seat. Australians like an underdog.
Some see Wentworth as a litmus test for Mr Morrison’s prime ministership.
Whichever way it goes, the harbourside electorate will be heading back to the ballot box with the rest of the country in around six months.