Lyle Shelton came of age on the grave of a volcano. There was no saving him from the flames. In the beginning, before the same-sex marriage postal survey and National Press Club appearances, before the Sky News interview slots and #eatshitlyle memes on Twitter, he served the Toowoomba City Church, a Pentecostal congregation started by his father, Ian, from the ashes of a right-wing cult.

“I worked in my dad’s church for three years,” he says, drinking tea at The Coffee Club cafe in Brisbane. “I was a youth pastor there. But I had politics in my blood. Our family discussions around the kitchen table were about politics and religion – the two subjects you should never talk about in polite company.”

The Garden City, in Queensland’s Darling Downs, was the dream location for an evangelist with ambitions of mainstream respectability. Toowoomba, Australia’s second-largest inland city, is well known for flowers, drought, conservatism and churchgoers. Rich soils fertilise its spectacular parks and gardens. There is a higher than average density of evergreen trees and “Love It or Leave It” bumper stickers.

If the Darling Downs is Australia’s bible belt, Toowoomba is its buckle. Citizens flock to heritage-listed Catholic and Anglican cathedrals. Those inclined to singing and literalist interpretations attend Pentecostal churches that resemble basketball arenas.

On the 2000th anniversary of Jesus’s controversial homebirth in a Middle Eastern manger, Shelton, the mild-mannered church worker, ran for council on a high-and-mighty platform of objecting to pornography, pokies, strippers and prostitution. He was Ned Flanders with a country Queensland twang, thin and neatly dressed with a good-natured grin.

“In the year 2000, the Beattie government was legalising brothels,” he recounts. “I said that’s a bad idea, because it’s legitimising the exploitation of young women. It’s funny, now there’s a big cohort of feminists who agree. It’s gone full circle, and we’ve got the #MeToo movement. So I feel vindicated by all that. But at the time, I was seen as a moral wowser, and I copped a lot of stick.”

Unsurprisingly, given Toowoomba’s reputation for godliness, Shelton romped it in. But in a stunning upset, the mayor elected to lead a traditionalist city was an independent feminist named Dianne Thorley.

Thorley was a lifelong underdog, a short-haired former pub chef who swore like a drunken sailor with Tourette’s. She didn’t wear make-up, jewellery or dresses. Her voice was husky from chain-smoking menthol cigarettes. At 19, she gave up a baby for adoption. Her platform featured personal honesty, empathy for the destitute and, presciently, environmentalism.

Two decades before #MeToo, Thorley spoke publicly about surviving a violent marriage with a Pentecostal wife-beater, and recovering to become a successful businesswoman. She describes her ideology as “pro business with a social conscience”.

“I don’t regret anything that happened,” she says to me over the phone, “because it taught me to empathise instead of sympathise with people.”

Despite front-page headlines questioning her femininity, and blooming rumours about her sexuality, one of Australia’s more conservative electorates voted for a single mum with an openly dark past to be the mayor instead of whipping her to political oblivion. It was a miracle.

How, I ask Thorley, did a self-described “weirdo” get herself elected as the mayor of a square city? The phone line purrs with slurped coffee and guttural puffs of cigarettes.

“I wouldn’t have a clue,” she says. “Maybe people respected me because I was friggin’ honest, and I wasn’t beholden to anyone.”

Despite receiving overtures from major parties, Thorley stayed fiercely independent. She was the antithesis of a career politician. She did rubbish collections with garbos at 4am on Christmas Day, left her number listed in the White Pages and wore jeans to City Hall.

When a graffiti artist persisted in tagging local buildings, Thorley brokered a bilateral ceasefire over a smoke in Queens Park. “I’ll rip off your dick that hard you’ll have to piss sitting down,” she told him.

Even more surprising than her election was that this self-confessed sinner enjoyed such an amicable working relationship with Shelton – the polite Christian and most right-wing member of council. She recalls evenings on the verandah where she humoured Shelton and his father’s attempts to preach Christianity, and to introduce Bible readings before meetings. She told them they’d need to introduce a roster along with the Muslims and Buddhists.

“They wouldn’t leave me alone. I’d say, ‘Fuck off Lyle! Just let me have a smoke and coffee in peace. I can’t be saved!’ I think eventually they realised I was going straight to hell.”

Today, Shelton describes Thorley as a “good woman” but a “mad believer in climate change”.

“Looking back now,” he says, “I’d say Di would fit comfortably within the Greens political party.”

Despite their ideological differences, Lyle says that working with Thorley remains a career highlight. “I liked Di a lot,” he says.

Thorley is less diplomatic about Shelton. Unlike the polite pastor, she doesn’t give backhanded compliments. She quotes Sun Tzu: “If you sit by the river long enough the body of your enemy will float past.”

“My mate the happy clapper?” she spits. “He’s a duplicitous little shit.”

In 2004, the yin and yang of Toowoomba politics swept back into power. Besides the mayor, Lyle Shelton was the only member of council to increase his vote. Dianne Thorley won re-election in a landslide. The supreme outsider had become a much-beloved leader.

Environmental catastrophe soon endangered Thorley’s popularity. Australia’s worst drought on record had been raging since 2001. The Darling Downs was particularly hard hit. Escalating water restrictions were imposed on a moaning population. Citizens were only allowed to water front lawns on certain days, and to wash cars with a sponge and plastic bucket.

In the country, farmers entered the bargaining phase of grief. They didn’t pray for rain. They daydreamed of sympathetic bankers, unforeseen inheritances and long-shot plots to stave off bankruptcy for one more season. In the suburbs, sheets of corrugated steel spread like melanomas across a sunburnt horizon, answering the cancer of drought with the radiation of fresh development.

By 2005, dam levels had fallen below 30 per cent. They’d drain dry within two years unless it rained. Thorley war-gamed doomsday scenarios with the state and federal governments. In 2006, the trainee federal minister for water was an Oxford-educated ex-merchant banker from Sydney named Malcolm Turnbull. True conservatives like Shelton believed his smart-arse smile hid a left-wing heart.

The suave future prime minister negotiated a deal with a fair dinkum mayor. It seemed simple. The cheapest and most environmentally friendly solution was to filter impurities from sewage through membranes, and pump the sterilised liquid back into dams. Under the plan, 25 per cent of drinking water would be purified sewage. Experts agreed this was the most feasible option. Bipartisan support existed at every level of government. Even Shelton supported it initially.

When asked by the media if he’d personally sip the recycled sewage, Turnbull grinned winningly at the camera.

“With alacrity,” he said.

Thorley appealed to a brittle sense of egalitarianism. “Water shouldn’t be the right and privilege of the rich,” she said. Her words struck panic inside the conservative heart of the city.

All hell broke loose. The Garden City – fertile breeding ground for tall poppy syndrome, spiritual home of the Silent Majority – was being tyrannised by faithless politicians and pretentious environmentalists.

A local woman, Rosemary Morley, started a group called Citizens Against Drinking Sewage, whose petition swiftly collected 10,000 signatures. Morley was sceptical about expertise. “Scientists are scientists,” she said. “They believe what they want to invent. We’ll be the lab rats for the rest of Australia.”

The astroturf uprising of anti-science evangelism was funded by millionaire Clive Berghofer, the Donald Trump of the Darling Downs. Berghofer had built a hotel and shopping centre empire in the 1970s while buying up swathes of developable land. Over the next four decades, he subdivided 10,000 housing blocks, becoming the wealthiest and most powerful individual in local history. He was mayor from 1982 to 1992 and a National Party state MP from 1986 to 1991. After the new millennium property boom, he donated $10 million to medical research.

Berghofer was a high-school dropout from the farm, who now lorded over a fiefdom from a humble home in a suburb that he’d subdivided with his bare hands. A blue-collar, down-to-earth tycoon. Equal parts Montgomery Burns and Homer Simpson. He hearkened back to the glory days when the dams brimmed with water and the city was ruled with common sense by men, not hysterical single mums.

Hospitals, sporting stadiums and helicopters had “CLIVE BERGHOFER” printed on them prominently due to his philanthropy. Berghofer wasn’t simply a man. He was a highly trusted civic institution. The name became a trademark that children learnt to isolate with the same swiftness as with the big M of McDonald’s.

“They keep saying it’s safe,” he said of the water plan in 2007, “but these things haven’t stood the test of time. Asbestos was safe. Agent Orange was safe. Thalidomide was safe. Look at all of them now. Who’s to say this recycled water isn’t going to be the same?”

Experts were aghast. According to scientists and engineers, recycled water underwent so much refinement that it would actually be much cleaner than current drinking supplies. Adopting the proposal would simply guarantee federal funding for a technology that was inevitable.

Berghofer wasn’t convinced. He believed the local economy would crash under Thorley’s plan, and that nobody wanted to live in a city kept hydrated by purified urine. Property prices would fall through the floor.

The crusade needed to recruit councillors for public credibility. Shelton underwent an epiphany. Along with two other councillors, he defected from a council previously united behind Thorley’s plan.

The local MP, Ian “Chainsaw” Macfarlane, got the political jitters. He talked Prime Minister John Howard into an intervention. Howard proposed that if Toowoomba wanted the federal funding for recycled water, they’d need to vote “yes” in a plebiscite. Thorley says the plan was doomed to fail from that moment given the “inherent conservatism” of the Garden City. She compared members of the “no” campaign to flat-earthers.

Citizens Against Drinking Sewage had a simple slogan: “IT’S OKAY TO SAY NO.” Morley, the leader of the group, attacked Thorley’s inherent classlessness.

“She’s got a chip on her shoulder that she’s got to prove her worth,” said Morley. “Well, that’s too bad. Not through my community.”

Shelton still sees the supporters of the subsequent “no” campaign as underdogs. “We were just a ragtag bunch who felt that the evidence didn’t stack up and we shouldn’t be the guinea pigs of the world,” he says. “So we kicked up a stink and that led to the plebiscite.”

Thorley says that her personal Judas on council is getting his David and Goliath comparison backwards. She believes Shelton betrayed her due to the persuasiveness of a politically conservative multimillionaire, and in return for preselection with the National Party at the next state election.

“The salesmen of this scare campaign were intelligent enough to know that fear would always win over facts,” she says, “and used that fear to achieve their hidden agendas. It’s pretty simple. Clive cared about flogging blocks of land. Lyle wanted to be in parliament.”

The rancorous dispute was fought on anonymous blogs and talkback radio shows, and in letters to the editor. A decade before Donald Trump waged war against fake news while being its main exponent, Berghofer paid for an eight-page imitation newspaper to be dropped in every Toowoomba letterbox, camouflaging his personal agenda as scientific facts.

The whole thing became a witch-hunt. Scandalous rumours, far more exciting than science, flew throughout town. Some were creative enough to combine corruption with homophobia. Global water syndicates paid Thorley $11 million. She was heading to Tasmania after the plebiscite with the bounty and a lesbian lover.

At the height of hostilities, a man walked down Thorley’s driveway after midnight with a petrol can. The sleepless mayor asked the aspiring arsonist if she could provide a lighter, perhaps seeing an easier way out than death by a thousand deceits.

In the lead-up to the vote, international news crews converged on the town. It was a debate that would plague the world well into the future: Where will the water come from? Scientists became the villains of a melodrama. Residents too well mannered to call the mayor a “bitch” or a “dyke” instead directed their venom at the professionals, telling ABC journalists exactly what they thought about the “experts” and their hifalutin’ “science”.

“I don’t trust scientists,” said one resident. “I trust God.”

This was about whom Toowoomba believed. Wicked women or genteel men? Highbrow scientists or jovial property moguls? The propaganda of Al Gore and Tim Flannery or the gospel of Jesus Christ?

“Right through Australia we are known as the Garden City,” said Berghofer. “Now we are the Shit City or Poowoomba.”

He was a PR genius. “Poowoomba” stuck, and it stunk. The citizenry saw themselves literally sipping from sewage spiked with birth control. He planted petrifying visions of a homegrown Chernobyl. Men developing breasts. Women sprouting facial hair. Babies growing six nipples. Everyone dripping with shit.

Sixty-two per cent of voters were opposed to drinking their own sewage. Capitalism joined forces with Christianity to win a scatological battle against science. The Garden City was now famous for two things: wasting vast amounts of H2O on an annual flower parade, and voting “no” to recycled water.

The victory was a false dawn for right-wing Christian populism. Six weeks after the referendum, Shelton ran for state parliament as a National Party candidate, still basking in the glow of Thorley’s political crucifixion. But he was heavily defeated by a Labor Party candidate, and retreated to the bubble of Canberra, where he disseminated policy positions based on scripture for the Australian Christian Lobby (ACL).

By her own admission, Thorley was spent at the end of her second term, due to the personal nature of the campaign and her insomnia-fuelled “mission” to rescue vulnerable kids. She fled to run a pub in country Tasmania, without $11 million or a lesbian lover.

Drought continued. Dam levels kept dropping. The government announced a pipeline from Wivenhoe Dam at roughly double the cost of recycled water. In 2011, Toowoomba flooded, along with many other parts of the state, filling dams to the brim – before relapsing into drought again.

The only real winner in the aftermath of Toowoomba’s civil war was Berghofer. Property prices rose despite the extreme weather cycle. In 2013, he bestowed a further $50 million of an estimated $320 million fortune on cancer research.

“I’ve got more money than the king,” he told the ABC in 2015. “But I give away $50,000 a week, and most of my money I give to Toowoomba.”

Today, recycled sewage is back on the cards, though PR experts have renamed it “reconstituted” water. On April Fools’ Day, water from Wivenhoe Dam was projected to start flowing into Toowoomba’s hydration supplies. When capacities drop below 40 per cent, pumps are automatically triggered at the region’s sewage plants, and the Garden City will finally get a taste of its own (reconstituted) shit.

I call Clive Berghofer and explain that I’m researching a story about Toowoomba. “You’re a writer?” he spits. “What kind of bloody writer?”

I make a quick pitch but he is unimpressed. He mutters indiscriminately for half a minute before hanging up.

Lyle Shelton is still licking his wounds after spearheading the “no” campaign at the 2017 same-sex marriage survey, and surviving the ridicule of left-wing Twitter activists.

In buttoned-up short sleeves, jeans and R.M. Williams boots, at the cafe in Brisbane he spins avuncular yarns about a left-wing conspiracy to brainwash the world with climate change.

“I think while ever you are fixated with ideology, you can make some terrible blunders in public policy. We are seeing that on a wider scale now, with our electricity market driven by Green dogma.”

Eleven years after victory in the recycled water debate, the nation rejected Shelton’s anti-marriage-equality campaign with identical figures – 62 to 38 per cent. Shelton is now on the rebound with Cory Bernardi and the Australian Conservatives. “Bring Back Common Sense,” read their billboards. “Vote Conservatives.”

Shelton gets a childish gleam in his eye while speaking about the recycled-water debate, so far the pinnacle of a hit-and-miss political career. He sees Toowoomba’s “no” vote as the genesis of current resistance to left-wing ideology and global-warming lies.

“I remember the mayor having Tim Flannery’s book on her desk in City Hall – The Weather Makers,” he says. “She was very influenced by that and by left-wing Green thinking. So she decided to go all out as if this was the gospel truth. She said, ‘The dams will never fill again! Climate change is real! You have to do this!’ And it’s been proven not to be true.”

If this is why Shelton fought so hard against her, Dianne Thorley has a sacred claim to fame. She was the first Australian political leader crucified over climate change. Clive Berghofer paid for the nails and handed Shelton a hammer. The recycled-water debate was a harbinger of the global-warming wars fought across a sunburnt country over the following years, sacrificing multiple leaders at the altar of radical apathy.

Thorley has risen again after more than a decade in the Tasmanian wilderness. I drive to Toowoomba to meet the city’s Joan of Arc in the flesh. On south-east Queensland’s Darren Lockyer Way, capitalism and Christianity wage an eternal battle for the eyeballs of drivers. Billboards advertising new subdivisions loom large alongside high-definition images of three-month-old foetuses and pro-life hotlines. “LAND AND HOME PACKAGES!” “HURT BY ABORTION? CALL THIS NUMBER!”

We meet downtown at the Australian Cultural Library. I thought Thorley was joking when she informed me she had recently joined the board of the ACL. The difference between her ACL and Shelton’s ACL is stark. The Australian Cultural Library recycles rare literature and art that would otherwise be destroyed.

In the library’s kitchen, Thorley dumps meatballs and coleslaw onto a plate. I wonder about the ethics of accepting lunch from a subject.

“For fuck’s sake,” she says. “Stop mucking around.”

Before we begin the interview, “Fast Car” by Tracy Chapman starts blasting through the floorboards. Thorley croaks with laughter. She says the tenant downstairs is a cafe where homeless people learn to be baristas. This doesn’t seem funny until she explains the hipster Christian couple who run the program are members of the Toowoomba City Church, where Shelton’s dad, Ian, remains supreme leader. She can’t escape them.

We sit on the fire-escape stairs, away from humanist librarians tapping piano keys and the faithful showing the forsaken how to make cappuccinos. Thorley draws a lighter from her bra and smokes continuously. She’d rather talk about the Murray–Darling and irrigation than recycle the personal slurs and outrageous identities of the water debate, but nonetheless reacts angrily to Shelton’s assertion she was a clandestine Green or that she ever read The Weather Makers.

“That’s all piss and wind and bullshit,” she says. “I was called a Lib for being pro business, or a Green for cleaning up the creeks. But I never sang from anyone else’s hymn sheet. Recycled water wasn’t part of some big left-wing climate-change conspiracy. The dams were empty! It wasn’t raining! That was the truth. This wasn’t a gospel story I came up with on a lazy Wednesday arvo to jam down people’s throats … You discover an issue, you listen to the experts, you find a solution.”

Thorley is a compassionate larrikin with a keen intellect – more policy wonk than populist. A speed-reader who needed to cut down to six books a week after getting elected, and a family violence survivor who gave her number to abused and homeless youth in case they needed a safe place to stay.

Her parting gift to Toowoomba was Sunrise Way, a detox centre for drug addicts – an expert-run alternative to the Christian facilities that prescribe abstinence and scriptures.

“I never told anyone this,” she says, “because I don’t like to be self-pitying. But I went home the night we lost the plebiscite, and it hit me: the voters believed I would put them at risk. When I’d busted my absolute guts to save so many people. I knew some would always hate me, or think I was a lesbian, or just didn’t want to drink piss. Who gives a shit? [ But there was] one thing that stung me: Clive Berghofer and Lyle Shelton let people think I would hurt them.”