One day in 2017, Fiona Patten took the biggest risk of her political career. Three years into her first term in the Victorian parliament, it was time to get serious. She became the leader of the party formerly known as Sex.

“I’m constantly told what a mistake I made,” the former leader of the Australian Sex party tells Guardian Australia. “Generally by the same people who told me to change the name in the first place. ‘Change your name, change your name … Oh, shit, why did you change your name?’”

More recently, the Reason party, successor to the Sex party, has quietly become “Fiona Patten’s Reason party”.

“I hope, I believe, that half the people voting for us in 2014 voted for our policies and possibly half voted for the name,” says Patten, who has held the balance of power in the upper house, along with the Greens and other minor parties, since 2014.

Her profile has risen dramatically since she was elected. Many of the state Labor government’s eye-catching social reforms – voluntary assisted dying, safe-access zones around abortion clinics, Melbourne’s first safe drug-injecting room – bear her fingerprints.

But Victoria’s upper house is tough to predict and the results often hinge on backroom preference deals.

A ‘lobbyist’ versus an activist

The upper house is divided into eight electorates, including the northern metropolitan region, which normally elects two Labor MPs, a Liberal and a Green. Patten won its fifth and final spot from the Liberals with about 11,000 votes in 2014.

The area stretches from Melbourne’s trendy, left-leaning inner city to its suburban fringe where, as Patten notes, there are “77 babies born … and 70 new housing applications” a week.

With the campaign to be dominated by law and order, Patten blames the Herald Sun, in part, for “running fear campaigns, which are not warranted and not helpful”.

On her agenda this time is a plan to tax religious businesses, and the decriminalisation of drugs. The former adult-industry lobbyist still sees herself as a lobbyist “but with more people’s mobile numbers and greater access to their offices”. A second term would be her last, she tells Guardian Australia.

“I think eight years is plenty,” she says. “I don’t have a cheque book so I can’t go out and promise ‘if I’m elected, I’ll build you a school’ and I sometimes resent the fact that other parties do that.

“[But] I can advocate effectively. So my message is, ‘I’m more responsible and a reasonable person’. And I hope that is what people want to see in parliament.”

Stephen Jolly, a construction worker and city councillor at the City of Yarra in Melbourne’s inner north since 2004, likes and respects Patten. But soon after the Sex party became Reason, Jolly formed the Victorian Socialists, coalescing the city’s divided leftist groups to fight an election together for the first time in a long time.

In Patten’s view, Jolly’s presence (you can’t walk 100m throughout Melbourne’s inner north without seeing his face on a poster) could “deliver [the seat] to the conservatives” by splitting the progressive vote, a claim disputed by some sources at Spring Street.

Khaldoun Taleb speaks with a Victorian Socialists volunteer in Arabic. Taleb says he only votes to avoid a fine. Photograph: Luke Henriques-Gomes/The Guardian

While Jolly has policy goals – a rent freeze and an audit of every business in the state to ensure they are paying legal wages among them – his main game is to turn “the northern suburbs of Melbourne into a stronghold of resistance”.

“It’s not about me making pretty speeches in parliament,” Jolly, 56, tells Guardian Australia. “It’s mainly about using the position to mobilise people.”

Behind the ‘quinoa curtain’

Patten’s party may have got serious but she hasn’t lost her sense of humour. With the election a few weeks away, Reason has been rolling out a series of slick ads across social media.

One in which she said she knew a lot about “dicks” – she meant politicians – was censored by Snapchat. Another says: “Don’t miss your chance to put one in my box.” To spruik its support for pill-testing, Reason is holding a five-hour rave at a Fitzroy bar next week.

Backed by a $50,000 donation from the Electrical Trades Union, Jolly has a decent profile close to the city. So he is looking north of Bell Street, an arterial road known – at least in newspapers – as the “quinoa curtain” or “hipster-proof fence”, where he needs to peel votes off Labor.

Which brings us to the tiny suburb of Dallas, about 17km north of the CBD, where 350 of its 2,000 workers were jobless at the last census. Next door in Broadmeadows – where Eddie McGuire grew up (his brother Frank is the Labor MP) – unemployment hovers around 25%, the highest in the state.

The Ford factory in “Broady” closed in 2016 and last year a recycling stockpile caught fire, blowing toxic fumes over homes for weeks. What it sees less often, Jolly says, are politicians.

At a local park, a large group of volunteers are told to emphasise Jolly’s promise to forgo an MP’s salary ($168,000) for an average wage. (He later defines this as $85,000, “equivalent to a skilled nurse in Victoria”.)

On the doorstep in Dallas, it is apathy, not antagonism towards a “socialist”, that he comes up against.

Few residents are keen to chat or speak much English. One man who does tells Jolly, midway through an impassioned pitch about transforming the former Ford factory into a new publicly owned recycling centre, that he is wasting his time.

“To be honest, because there are fines, that’s why I go to vote,” another local, Khaldoun Taleb, says. “Otherwise, I feel there is no change. It’s the same bullshit.”

Taleb, a father of four, has invited a Victorian Socialists volunteer on to his porch to chat in Arabic. He gestures towards his pack of cigarettes (“I can’t stop”), which, like “everything”, keeps “getting more expensive”.

Taleb owns his home and his work truck, which is parked in the driveway. There is not enough work. “I work one day, and I sit for 10 days,” he says.

At the last election, Labor claimed almost half of the 36,000 upper-house votes up for grabs in Broadmeadows, including Taleb’s. The Liberals had 6,000, the Greens got 1,700. The Sex party’s 774 votes here were only marginally fewer than it garnered in socially progressive Brunswick. (The informal vote was 3,289.)

Taleb is polite when asked about Jolly’s campaign, but says: “It’s all just promises.”

A few days later, sitting in the beer garden of a pub near her Brunswick office, Patten admits feeling “very nervous” about her prospects. She worries that parliament passed safe access zones and assisted dying only by a couple of votes.

“If the Legislative Council was to change and we were to see the crossbench lean more towards the conservatives’ end of the spectrum, the battle will be back on for abortion rights, the battle will be back on for assisted dying,” she says.

And if it ends on 24 November? “I think we can look back and say we’ve been a pretty effective independent member,” Patten says. ‘“Win, lose or draw, I think parliament will be a different place as a result.”