There has been a church here for close to 500 years. For the last five years, it's been Prosman's home.
On an average Sunday, he says, about a third of the 800 villagers will come to attend his service.
Prosman tells me that he doesn't consider himself a prototypical nationalist, but he increasingly finds himself echoing the concerns of his rural parishioners.
The village looks and feels typically Dutch. Ducks splash around in the water; a few feet away, villagers amble between shops and stop to chat with friends.
It's a stone's throw from Amsterdam, but Nieuwkoop feels a world away from the bustle and tourists.
Prosman grew up around here. His father was a church minister before him. His grandfather was a local reed salesman in this region, famed for its peat and bull rushes.
At one time, both were staples of local commerce, but over the past few decades, Nieuwkoop, Prosman says, has become typical of many similar villages: they've become Holland's rural rust belt.
Peat and rushes are no longer in the same demand and employment patterns have changed, leaving many of Prosman's congregation uncertain about the future.
They are worried about the economy, he says, about the welfare system and about healthcare, but most of all about rising crime -- something many of them blame on Muslim immigrants.
Prosman's plain but welcoming 19th-century church replaced an even older one built in the 1500s. In an era of uncertainty, it has become a reassuring beacon of continuity and identity.
In Holland today, Prosman explains, the major political parties are hemorrhaging followers.
There is a crisis of confidence in the European Union's old elites. The integration and open borders that they sold supporters are past their expiry date.
"I think people get it. And they don't want it," Prosman says of the EU.
Prosman, who is not only a minister but also writes books on political science, says that his religious calling puts him far closer to the people than regular politicians.
His congregation confide in him, he says, in a way they wouldn't with others.
Mainstream political parties are out of touch, leaving many of his congregation turning to populist Geert Wilders for guidance and answers.
He tells me that Wilders' appeal mirrors the rise of Donald Trump: "I think it's the same in Holland with Geert Wilders: his voters take him seriously not literally," he says, whereas politicians "tend to take him literally."
Like Trump, Wilders' popularity is rising
One of Wilders' hot button issues is Muslim immigration: even in tiny rural Nieuwkoop, Prosman says it resonates.
He claims that public housing is being given to immigrants and that it is "very hard for young [Dutch] people to find a house."
In the 2006 general elections, Wilders' PVV (Party For Freedom) won 5.9% of the vote. In 2012, it won a little over 10.1%.
Ahead of national elections here March 2017, polls predict that the party may get about 20% of the vote, making it the largest party in Parliament.
Where Trump has said many Mexicans are criminals, Wilders blames Muslim migrants -- in particular Moroccans -- who make up barely 2.2% of Holland's population.
He's been to court more than once on hate speech charges.
But the court found him not guilty of incitement to hatred and handed down no punishment.
But why do people back Wilders?
Not far from Nieuwkoop, Financial Administrator Cindy van Kruistum is a fervent supporter of Wilders.
We meet in her smart, middle-class house, where her daughter's running watch is charging on a white table in her pristine kitchen.
If she wasn't meeting with me, she says she'd be out playing tennis.
The occasional car passes by on the quiet tree-lined road outside her large living room window; more frequently, her neighbors cycle past on the broad bike path.
It seems like the Dutch idyll so many of us imagine.
Yet Cindy tells me that on a street close by, her friend's son was mugged by a Muslim migrant.
It's not an isolated case, she warns. She follows a TV program that documents many such attacks. Wilders has the only answer, she says.
"I support him because he dares to talk about the problems we have with Islamization ... if they don't want to integrate, they should leave", she says, quoting Wilders' campaign rhetoric.
I ask if she is racist.
Quite definitely not, she replies: "My youngest daughter has a friend from Morocco ... and he fits in very well."
Wilders, she says, is the only politician who is in touch with the people. He understands what's happening.
She says: "The government, the establishment, they don't listen to the people. They don't go on the streets. Geert Wilders, he is near the people on the streets."
It feels as if we are far further from Amsterdam and its liberal trappings of dope-selling coffee shops and in-your-face red light districts than the hour drive away it actually is. But as Cindy explains, what the Dutch really treasure as their culture is under threat.
"The values we have in our country and the traditions we have in our country, they don't give a damn about it," she says, in reference to Muslim immigrants.
"The next thing you know they'll want to ban gays walking hand in hand in the street -- and that sort of freedom is important to us."
Cindy is not the only one to give me precisely that example of tolerance under threat.
Comedy writer Haye van Heyden told me the same thing.
His reasons for supporting Wilders are different from Cindy's, although like her he is frustrated with mainstream politicians.
He tells me he was ostracized by friends and lost work after he wrote an article explaining his support for Wilders.
"It's undemocratic", he says.
Indeed, punishing those who express their views is part of what angers him about Holland's traditional politicians. He says they refuse to deal with Wilders, instead accusing him of being racist.
I ask him if supporting Wilders makes him a racist. Like Cindy, he says absolutely not.
"I'm not a racist. I am very sure of it but I feel I have to protect the people who have their doubts about Islam."
He tells me he doesn't like everything Wilders says, but that he wants to stand up for the rights of all those who do believe him. "I'm voting for Mr Wilders. It's a protest vote because of the exclusion of him and his followers."
Minister Prosman echoes van Haye's sentiment: not everyone following Wilders is a nationalist, but they have given up on mainstream politics.
"It's a wake up call for politicians," he explains. "No one votes for Wilders out of principle, but they want to make sure they are heard."
It is perhaps no surprise that Prosman has become a natural confidant of his congregation.
His church is an epicenter of calm continuity amidst a world of change outside.
Mainstream politicians might do well to stop by once in a while.