Chris Tackett started tracking extremism in Texas politics about a decade ago, whenever his schedule as a Little League coach and school board member would allow. At the time, he lived in Granbury, 40 minutes west of Fort Worth. He’d noticed that a local member of the state legislature, Mike Lang, had become a vocal advocate for using public money for private schools – despite the fact that Lang campaigned as a supporter of public education.

With a little research, Tackett found that Lang had received hundreds of thousands of dollars in campaign donations from the Wilks brothers and Tim Dunn, billionaire megadonors whose deep pockets and Christian nationalist views have consumed the Texas GOP. Tackett published his findings on social media, and soon enough, people started asking him to create pie charts of their representatives’ campaign funds. These charts evolved into the organisation See It. Name It. Fight It.

“There’s so many people out there that are so busy with their daily lives, they’re walking past and not even seeing some of these bad things going on,” he says. “So that’s the first step: you have to see this thing.”

Tackett and his wife Mendi, the organisation’s sole members, now live in Fort Worth, where they’re part of a scrappy community of progressives and anti-extremist organizers who are building momentum amid their town’s deeply embedded Christian nationalism. Tarrant county, in which Fort Worth is the largest city, provided a chilling preview of Texas’s gerrymandering efforts, and the county is widely regarded as a hotbed for far-right actors. But most recently, the county was the site of a Democratic victory that sent the Texas Republican party reeling.

Taylor Rehmet, a Democrat and local union leader, won a runoff for a state Senate seat that’s been held by Republicans since 1992. What’s more, he bested Republican Leigh Wambsganss despite having one-tenth as much money. Much of Wambsganss’s funding came from Dunn and the Wilks brothers.

Republicans blamed low turnout for Rehmet’s victory, while pundits opined that the Trump administration’s unpopularity was to blame. But people in Fort Worth say local organizing was central to the upset – and it will be key to any future victories in Texas, too.

Alexander Montalvo, a longtime grassroots organizer in Tarrant county, points to several examples where local advocates have successfully rallied for causes they believe. There was the pushback against a proposal to split a local school district. Then there were the school board elections last May, where every candidate endorsed by the Christian nationalist cellphone carrier Patriot Mobile lost their election. Patriot Mobile – where Wambsganss works as an executive – had previously racked up several wins across Tarrant county, effectively taking over multiple boards.

Now, after those May losses and Rehmet’s win, the company’s political influence is in doubt.

“There is something very local here in Tarrant county that is happening and that has been happening,” he says. “There is a collective groundswell that’s been building.”

Tackett says he’s in close contact with organizers like Montalvo and other Tarrant County residents who meet up for what’s called the “817 Gather”: a monthly meeting of people activated by the extremism that’s run rampant in their area.

“It’s a bunch of folks that are Black, brown, white, mostly progressive, but we’ve got a few folks that play into that former Republican space, as well,” he says. “It’s not about Republican versus Democrat. It’s really all about what we stand for, because we can agree that public education is foundational to the success of our democracy. We can agree that a person should have rights over their own body, and it should be easier to vote, not harder to vote.”

People have found their roles within this community, and in one way or another, their efforts always lead back to voting. Montalvo and fellow organizer EJ Carrion, one of the hosts of the local podcast the 817 Pod, frequently inspire large crowds for local city council and county commissioner meetings. The Tacketts publish social media videos spotlighting their concerned neighbors – often as they speak at those local meetings – and putting local extremists on display.

Before Rehmet’s victory, their organisation shared a video of Wambsganss appearing on the podcast of former Trump consigliere Steve Bannon. After the election, the Tacketts published a video breaking down how local Republicans reacted to the Rehmet victory at a meeting held the day after Rehmet’s win.

In the video, a candidate for Texas agriculture commissioner claimed Texas was at risk of falling under Sharia law. Others framed politics as a spiritual battle that will determine whether the US remains a Christian nation. That meeting was hosted by For Liberty & Justice, a local political organisation affiliated with a Fort Worth church called Mercy Culture which is seeking actively encourage conservative Christians to run for office and break down barriers between church and state in the US.

When it comes to Christian nationalism in Tarrant County, multiple people interviewed for this story say no institution looms larger than Mercy Culture.

“Mercy Culture is not just a church,” says Wesley Kirk, a lifelong Fort Worthian and one of the hosts of the 817 Pod. “It’s a political machine. They are organizing people. They are endorsing candidates.”

Chanin Scanlon, a former Fort Worth resident who recently moved to San Antonio, puts it bluntly.

“This is Christian nationalism,” she says. “It’s not subtle. They are very clear about what they want. They want to take over institutions.”

The Tacketts have used their popular social media presence to chronicle Mercy Culture’s rising influence. But Chris Tackett is also still making pie charts. After the Rehmet victory, he dove deep into the data to see if the narrative about low turnout was true. Turnout was down across the board, he found, which undermined the local GOP’s narrative that Republicans who stayed home were the ones to blame.

Using a voter score analysis, Tackett also found that 57% of runoff voters fell into one of two groups: true independents, or “Democratic-leaning voters who regularly vote in Republican primaries because, in ‘deep-red’ Texas, the GOP primary is the only election that matters in most cycles.” (Fifty-seven percent is the total percentage of the electorate that Rehmet won.)

“What we saw wasn’t massive Republican crossover,” he wrote. “It was Democrats – many of whom have been forced to play in GOP primaries for years – finally getting a meaningful choice and showing up.”

Brandon Rottinghaus, a political science professor, agrees with the idea that Democrats had a strong candidate to back in the runoff.

“I think they figured out the secret sauce to candidate recruitment,” he says of the Democratic party. “Being an authentic person goes a long way for voters these days.”

Montalvo, meanwhile, finds himself motivated by Tackett’s pie chart.

“There’s actually a big enough and a diverse enough base amongst Democratic voters in Tarrant county that if we actually invest in those communities, we have the votes to be able to win,” he says.