Monticello, Iowa (CNN) Since Donald Trump came along, they have a "safe word" at the Table of Knowledge inside Darrell's Diner in Monticello, Iowa.

As men with hands calloused in the fields debate the fitness of a leader more comfortable on a golf course , things get heated. And when debates turn to insults, one of the retired farmers will say, "What's a good time to trim your rosebushes?"

The phrase is a reminder to get back to "Iowa nice" and remember they'll need cool heads for their friendships to survive the most divisive presidency of their long lives.

"They got into it one day and I was worried," says Jerry Hahn, one of the retiree regulars. "So 'rosebushes' is the safe word."

There are actually two Tables of Knowledge at Darrell's, a joint that's been serving up hot coffee and conversation since the Truman administration.

Sit at the conservative one and you'll hear strident defense of the man who won this county -- which voted for Barack Obama twice -- by a staggering 20 points.

Friends and neighbors joust over politics more than ever these days in Darrell's diner.

Wander over to the more liberal Table of Knowledge and you'll hear mocking outrage of the 45th president.

But the real fun begins when the two tables mingle.

"Trump pulled the wool over their eyes," retired farmer Mel Manternach says about the two Republicans sipping coffee next to him. "But his base has not recognized it."

Gerald Retzlaff pushes back. "Trump wasn't my first choice. However he is doing a hell of a good job," he says. "He's playing three-level chess versus everybody else playing checkers."

Gary Fisher, the local eye doctor, rolls his eyes and lowers the boom. "The ones that are supporting Trump are either greedy or they are bigots or just don't see it yet," he says.

Farms surround the town of Monticello, Iowa.

"If the vote were taken today, I think things would be different."

Over at the counter sit Richard and Brian Wolken, living proof that Trump divides families as well as diner seating in Monticello.

Richard, a farmer and one of the town's three dentists, is "100% Trump." "You know I go back to Nixon," he says. "I was with him all the way. That's just hardcore Republican conservatism."

His 34-year-old son, the town's mayor, winces. Brian traveled the world before coming home to farm and run for local office. He supported Bernie Sanders and can't understand his father's loyalty to Trump after a year of scandal, turmoil and rhetorical flame-throwing

"Farmers are pretty stubborn," he says, glancing around a diner full of them. "They have to be, by the nature of their jobs. They're going to ride the storm out and you're not going to see that buyer's remorse as much."

Farmers also are a good example of how information and media have shaped Trump's approval ratings across rural America.

Iowa voted for Barack Obama twice, then swung to Donald Trump in 2016.

On the Wolken farm you can tell which member of the family has been working the fields by the station on the tractor radio.

If it's WMT out of Cedar Rapids, the local AM home of Rush Limbaugh and Sean Hannity, that means Richard the patriarch has been out spraying corn.

But if NPR comes out of the speakers, his son drove it last.

Out at the nearby Adams farm, "We do not watch the news," says Renee Adams. "Stuff just seems too negative and we're busy with other things."

At the Adams' farm in Monticello, the children learn by looking after their own animals.

Those "other things" include five children, a few thousand hogs and 800 acres of corn and hay. It's no wonder that the Adamses don't follow the tweet-by-tweet drama coming out of Washington.

She says that she and her husband Chad supported Trump after the family's health insurance premiums went up by $5,000 and they give him major kudos for becoming the first president in 25 years to address the annual American Farm Bureau Federation meeting. "You know I haven't seen that from other presidents," she says.

But while his words played really well around Jones County, Iowa, Trump's actions could could end up hurting Renee and her neighbors.

Sam Clovis, Trump's nominee for head scientist at the Department of Agriculture, was not a scientist and was forced to withdraw after becoming entangled in the Mueller Russia probe.

He scrapped an Obama's Fair Farm Practices rule that would have offered legal protection for family farms against unfair corporate meatpackers.

"They're just pandering to big corporations. They aren't interested in the family farmer," said Iowa's Republican Senator, Chuck Grassley, after the move. "The USDA is the US Department of Agriculture, not the US Department of Big Agribusiness."

Chad, Renee and Doug Adams raise hogs and grow feed at their family farm in Monticello.

But the move that worries Trump's rural base the most is his threat to scrap the North American Free Trade Agreement

"Now with NAFTA, that's another story," says Renee as she stands in front of a brand-new hog barn, the biggest investment of their lives. "You know that does scare us pretty bad. We would go bankrupt."

"I'm sure he has a plan if he does pull out," her husband shrugs. "I don't know what that plan is."

There's not much foot traffic in Monticello, but the conversation inside the diner is always lively.

Meanwhile, back at Darrell's, Gerald is singing the praises of the booming stock market and floating a conspiracy theory that the Clintons may be tied up with dozens of deaths.

"They are so ingrained with the crotch-grabbing liar," says Mel. Things get uncomfortably quiet. And then it comes:

"When's a good time to cut my rosebushes?"

Correction: A previous version of this story inadvertently attributed a quote about Trump supporters to Ken Weber. This story has been updated to correctly attribute the quote to Gary Fisher.