Throughout Donald Trump’s presidential campaign, there was nearly constant uncertainty among voters about how seriously to take his promises.

In August, Kellyanne Conway backtracked on Trump’s pledge to create a deportation force to rapidly remove undocumented immigrants, saying his plan was “to be determined”; in October, debate responses revealed that Trump and Mike Pence disagreed about military intervention in Syria; in November, Trump told the New York Times that there is "some connectivity" between human activity and climate change despite previously deeming it a Chinese hoax.

That changing rhetoric likely allowed Trump supporters who approved of many of his messages to disregard the others that they didn’t agree with, deeming them little more than talk. But that approach has since left Trump-supporting California farmers worried about the implications of their votes.

According to the New York Times, conversations with nearly a dozen farmers revealed that while most voted for Trump, they all rely on workers who provided false documents. Many didn’t believe that Trump would actually build his proposed border wall between the US and Mexico, or deport workers who lacked proper paperwork. But the series of executive orders the president signed during his first few weeks in office have already disrupted the US immigration system and put the country on a path toward severely restricting trade. Trump's actions, in other words, have suggested that his promises were literal.

California’s fields provide more of the nation’s food than any other state — its cash farm receipts in 2015 represented nearly 13 percent of the US total, according to a report from the state’s Department of Food and Agriculture. And according to the National Agricultural Workers Survey (NAWS), conducted by the Department of Labor, about half of all crop farm workers in the US are not legally authorized to work in the country. Other estimates put that portion as high as 70%.

If Trump follows through on his promises of mass deportations, the agricultural economy in California and elsewhere would be severely damaged.

“If you only have legal labor, certain parts of this industry and this region will not exist,” Harold McClarty, a fourth-generation farmer in Fresno County told the Times. “If we sent all these people back, it would be a total disaster.”

Bruce Goldstein, the president of Farmworker Justice, a nonprofit that aims to improve farmers' living and working conditions, put the problem in even more dramatic terms at a recent summit. ”If we were to engage in massive deportations, our agricultural system would collapse," he said.

Other businesses that depend on farm workers as clients would also be impacted by a sudden disappearance of undocumented laborers — a gift-shop owner and an insurance agent in Madera County both told the Times that kind of change could send their businesses into severe decline.

Trump’s proposed changes to US trade policy have also caused growing concern among farmers. Within days of taking office, Trump withdrew the US from the Trans-Pacific Partnership, and has vowed to renegotiate NAFTA to gain more favorable terms for the US. Press Secretary Sean Spicer also floated the idea of a 20% tax on imports from countries like Mexico to fund construction of the border wall.

If the Trump administration does wind up imposing import taxes or simply pulling the US out of NAFTA, farmers run the risk that countries impacted by the policies could retaliate, a move that would hit farmers hard. According to the LA Times, many farmers have seen double-digit growth in commodities like soy beans, dairy products, grains and meat since the mid-90s (NAFTA went into effect in 1994).

California farmers would have the most to lose in that scenario — approximately 26% of California’s agricultural production was exported in 2015, a total of $20.69 billion. The state is the sole US exporter of almonds, dates, garlic, olives, table grapes, and more.

Many farmers who remain loyal to Trump are still hopeful that his opposition to environmental regulation will prove beneficial to their operations. According to KQED, some California farmers blamed conservation-based policies for their lack of water over the last several years. At a rally in Fresno, Trump promised to “start opening up the water.”

Others still have faith that the president's experience as a businessman will lead him to realize the consequences of mass deportations and come up with a more nuanced approach. And there is always the possibility that a renegotiation of NAFTA could wind up in the agricultural industry’s favor.

For now, California farmers will have to wait and see which of Trump’s policy proposals actually take root.