RUTHFULLY YOURS

For a red-state Republican in a tight election, these rolling visits are the arrival of the cavalry. Mr. Cramer is asking voters to promote him to the Senate this fall, and his success will be pivotal if the GOP is to keep majority control. The incumbent Democrat, Heidi Heitkamp, is so personally popular that Mr. Cramer confesses in one TV ad that “we all like Heidi.”

Yet North Dakotans also backed Mr. Trump in 2016 by nearly 36 points. “They are very supportive of this president,” Mr. Cramer tells me. He tilts his head and grins a little: “I mean very supportive.” Hence, Mr. Trump’s third official visit to the state, touching down Air Force One in Fargo this Friday to talk up Mr. Cramer at a $500-a-person fundraiser. “He’s gonna vote with me. He’s going to vote on Making America Great Again,” Mr. Trump told the crowd. If that doesn’t convince, the president is expected back in North Dakota for another rally before the election, and there’s Donald Trump Jr.’s planned speech on Sept. 25, not to mention . . .

One potential hang-up is Mr. Trump’s trade war, which could soon cost North Dakota farmers hundreds of millions of dollars. In 2012 Ms. Heitkamp won election by 0.9 percentage point, or 2,936 votes. Since the state has 30,000 farms, even a small tariff revolt could swing the balance. So far there hasn’t been much reliable polling. A June 13-15 survey gave Mr. Cramer a 4-point lead, within the margin of error, but that was before China put a 25% tariff on U.S. soybeans.

Typically, more than two-thirds of North Dakota’s soybean crop goes to China, shipped via ports in the Pacific Northwest: 60 pounds a bushel; 400,000 bushels carried by a 110-car train; just over five trainloads to fill a Panamax bulk ship. But since July there have been zero orders from the Pacific Northwest, industry data show. Soybean futures on the Chicago Board of Trade have fallen 20%, from highs near $10.50 a bushel to below $8.50. Meanwhile, the bite taken at the local elevator, which reflects demand and shipping costs, has grown. Instead of something like 85 cents, it’s hitting $1.50, as the market contemplates the difficulty of having to send soybeans east to St. Louis or Duluth, Minn.

“Cash prices in our area are $7.20 for harvest. Well, a lot of guys’ break-even is $8.50,” says Matt Gast, 33, who farms near Valley City. “We want fair trade, but how long can we go on doing this? Or is this the right way to do it?” With nowhere to send soybeans when harvesters start running in coming weeks, some farmers may have to dump backlogged crops into piles on the ground. Relief payments from the federal government, set at $1.65 a bushel for half a farmer’s soybeans and 1 cent a bushel for half his corn, may help cover operating loans. But they won’t fill the hole, and anyway everyone agrees farmers want “trade, not aid.”

If Ms. Heitkamp is looking for an opening with Trump voters, this may be it. “I will be damned if this trade war is going to be fought on the backs of North Dakota agriculture,” she tells a roundtable at Fargo’s area Chamber of Commerce. She has sponsored an as-yet-unsuccessful bill with Sen. Bob Corker (R., Tenn.) to require congressional approval before the president can impose new tariffs on national-security grounds. The true security threat, she asserts, is Mr. Trump’s withdrawal from the Trans-Pacific Partnership: “We are 5% of global population. The biggest asset we have is our partnerships with our trading partners.”

The opposite pitch comes from Commerce Secretary Wilbur Ross, who visits Fargo at Mr. Cramer’s invitation. “Guess what our cumulative trade deficit with Mexico—a small country—is since Nafta: $1 trillion,” Mr. Ross says. “Think how much better that would have been spent on infrastructure, on education, on military, on just about anything you can imagine.” Farmers, he adds, had nothing to do with American steel tariffs, but they’ve been unfairly targeted for retaliation because they supported Mr. Trump. “Many of you trusted the president in November of 2016 and voted for him,” Mr. Ross says. “Trust him again, and you’ll be happy with the long-term result.”

Mr. Cramer takes a similar tack. Tariffs aren’t his preference, he has maintained, but North Dakotans should support Mr. Trump as he pursues better deals. Agricultural groups seem surprisingly open to this argument. “The North Dakota Farm Bureau has very much supported the renegotiation of trade deals to correct years of imbalance,” Chad Weckerly, one of its board members, tells Messrs. Ross and Cramer, before asking the administration to pursue a resolution “with expediency, but not haste.”

Maybe the chatter among farmers in the field, out of official earshot, is saltier. Or perhaps the anger, as of late August, is a few weeks underripe. “A lot of farmers have not talked to elevators,” says Simon Wilson, who leads the North Dakota Trade Office, “and don’t realize that there may not be the cash option to show up at the elevator at harvest and say, ‘here’s a couple thousand bushels of beans.’ ”

Nancy Johnson, head of the North Dakota Soybean Growers Association, thinks farmers are still “trying to figure out how upset to be.” Even Mr. Cramer expects things to get worse before they get better. “Every week,” he says, “the anxiety level rises a little bit—obviously—because harvest comes whether you’re ready for it or not, and whether you have a trade deal or not.”

Yet there’s no getting around that many North Dakotans believe Mr. Trump is right on the merits. Mr. Cramer says that when reporters from places like MSNBC go trolling for angry farmers at the state fair, they wind up disappointed. “You have to kind of look hard even to find a pissed-off farmer to put on TV,” he says. “First of all, they’re just very patriotic. And they’re so tired of being lectured to by presidents and administrations and bureaucrats—pffftttt.” He sticks out his tongue and blows a raspberry.

This brings us back to Ms. Heitkamp, the Democrat, who brags in one campaign ad that she votes with Mr. Trump more than 50% of the time. “Frequently, if you’re like me, you have to disappoint people in your own political party if you’re going to do what’s right for North Dakota,” she tells me. Asked for a few examples, she replies with a laugh: “Oh, where do we begin?”