“They were annoyed,” Sleight said of his customers, who wanted to know just why the president thought NAFTA was such a bad deal. They also weren’t pleased, Sleight said, about Trump’s general comments on Mexicans, whom Trump described as “rapists” and “criminals.”

“They were insulted, really,” Sleight said. “For us, you don’t do that to your best customers.”

Last week, the top agricultural officials from the U.S, Canada, and Mexico met in Georgia to discuss the upcoming NAFTA renegotiations. While each country said there were some “irritants” in the deal, they overwhelmingly wanted NAFTA left alone. But because of Trump’s professed opposition to aspects of the agreement, farmers in the Midwest, import-and-export associations in southern Arizona, and big national agricultural groups like the one Sleight runs are already seeing a negative impact, and it may be too late to undo some of the uncertainty. On his visit to Mexico, Sleight said he constantly heard talk from Mexican farmers of a “Plan B,” as in a backup option in case they couldn’t buy or sell their products to the U.S. Some Mexican customers had even met the week before with representatives from Argentina. “You know,” Sleight told me, “those markets are critical. If we were to lose those you can’t make that up. You can’t just snap your finger and make that up.”

Like with any trade deal, NAFTA created winners and losers. In Florida, the tomato industry took a hit as it was forced to compete with western Mexico’s similar growing climate. Mexico’s grain industry couldn’t compete with the much larger and mechanized Midwestern operations. But because Mexico couldn’t meet its own demand for grains to feed livestock, Mexican ranchers could import U.S. grains at lower prices, spurring the Mexican livestock industry. Now ranchers raise their animals and oftentimes export them to the U.S. to be slaughtered, processed into meat, and, in many cases, shipped back to Mexico to as food. Canada, on the other hand, signed a bilateral trade deal with the U.S. in the late 1980s, so when NAFTA came much of the trade jockeying had already worked itself out.

It’s also helped that agriculture is seasonal. NAFTA ensures that fresh vegetables appear in supermarket aisles all year round, and it has generally made produce much cheaper. Lance Jungmeyer, president of the Fresh Produce Association of the Americas, an import-and-export association based on the Arizona border, told me that back in college he remembers wanting to grill vegetables, so he drove to the store and all he found were these sad, shriveled bell peppers. Go back 30 years, Jungmeyer said, and same went for blueberries or sweet corn, which were fresh on shelves for a few weeks. “Now you go to the store and you get whatever you want.”

Few in the agriculture industry believe NAFTA will end, and those I spoke with said Trump is a businessman; there’s no way he’d end it all. “But in the meantime,” Jungmeyer said, “when you have a threat, or even the possibility of a threat, of shutting down trade, that creates a real concern in people’s lives. They certainly are very worried about what next year looks like.”