“NAFTA is a bad joke,” wrote President Trump last week on Twitter.

For me and countless other farmers, however, the possible death of NAFTA is no laughing matter.

Instead, NAFTA is our lifeline.

Here in rural North Dakota—in what we might call “Trump Country”—our livelihoods depend on our ability to sell what we grow to customers in Canada and Mexico.

So as the president’s trade diplomats continue their NAFTA negotiations in Montreal this week—in what the Wall Street Journal says “could be a make-or-break round of talks”—I hope they have a proper understanding of how much we count on this trade agreement.

If the United States quits NAFTA, then the United States quits on its farmers. It’s that simple: Withdrawal would devastate us. We wouldn’t just lose our jobs. Some of us could lose our homes and our farms.

American farmers already export about half of our wheat and about one-third of our corn and soybeans. If we can’t rely on Canadians and Mexicans to buy these commodities, we won’t need to grow nearly as many crops. And that means we’ll need a lot fewer farms and farmers.

The heartland could suffer a new depression—not because of a long drought or a stock-market collapse, but because of a poor political choice.

Several years ago on our farm, we started to grow pinto beans for the Mexican market. North Dakota is a border state, but we border the Canadian provinces of Manitoba and Saskatchewan. The Rio Grande River is something like 1,500 miles away from our farm. Yet we’re now exporting a dozen or more boxcars of pinto beans to Mexico each summer—and looking for ways to expand.

Last fall, we made a significant infrastructure investment that will allow us to boost this area of our business. Mexican buyers want their pinto beans to arrive in 100-pound bags. This project will help us deliver exactly what they want.

And it will help our farm because it will improve our competitiveness.

There are other beneficiaries, too. To complete the project, we’re employing construction workers. Once we’re up and running—probably by June—we’ll buy power from a rural electrical cooperative.

None of this would be possible without NAFTA. If President Trump terminates the trade pact, however, we’ll miss out on a new economic opportunity involving pinto beans. It gets worse: We’ll also lose our investment. I don’t want to say how much we’re putting into this project, but it’s a substantial commitment.

I’ve always thought that one of the main purposes of U.S. trade negotiations is to put America first. That means finding ways for American farmers and manufacturers to sell more of what we grow and make.

One of the great ironies of the NAFTA renegotiation is that if it fails—which is to say, if the United States withdraws from the trade agreement—the people who will hurt the most are among some of the president’s biggest supporters.

In North Dakota in 2016, for example, 63 percent of voters favored candidate Trump. That’s a commanding majority—and only in four states were Americans more likely to vote for him.

Many of us in North Dakota appreciate President Trump’s first-year achievements. New federal judges will respect property rights and the Constitution. Regulatory relief will allow us to work the land without bureaucratic meddling. Tax reform will let us keep more of what we earn and make it easier for our children to inherit our family farms.

Losing NAFTA, however, could wipe out these accomplishments.

Regulatory reform won’t help us if we aren’t planting and harvesting.  Tax reform and estate-tax changes won’t benefit our family farms if we are not making a profit or forfeit the farm in an economic slump.

If this fate comes to pass, you might say the joke will be on us here in Trump Country.

It would be a really bad joke.

A version of this column first appeared January 25 at The Hill.