A push by the Trump administration to boost agricultural exports under the North American Free Trade Agreement could unintentionally increase illegal immigration from Mexico to the U.S.

Before NAFTA was implemented in 1994, then Attorney General Janet Reno said, “NAFTA is our best hope for reducing illegal immigration, in the long haul.”

However, the deal allowed American agricultural goods, specifically corn, to flood Mexico at cheap prices, which hurt farmers’ business and pushed them north to the U.S., according to experts.

A New York Times article earlier this year noted, “A 2014 study estimated that 1.9 million agricultural jobs were wiped out, mainly those of small family farmers, helping to drive more illegal immigration into the United States.”

Mexican journalist Alejandro Paez Varela told the New Yorker that American exports “created fifty-three million very poor people for whom the only solution is to emigrate, en masse, to the United States and send remittances home.”

The U.S., Canada, and Mexico are in the midst of NAFTA renegotiations and the guidelines for a deal set out by U.S. Trade Representative Robert Lighthizer entail boosting American agricultural exports.

“Expand competitive market opportunities for U.S. agricultural goods in NAFTA countries, substantially equivalent to the competitive opportunities afforded foreign exports into the U.S. market, by reducing or eliminating remaining tariffs,” a summary of the negotiating objectives states. “Seek to eliminate non-tariff barriers to U.S. agricultural exports including discriminatory barriers, restrictive administration of tariff rate quotas, other unjustified measures that unfairly limit access to markets for U.S. goods, such as cross subsidization, price discrimination, and price undercutting.”

Laura Carlsen, a Mexican journalist and the director of the Americas for the Center for International Policy, told The Daily Caller that these objectives “will make the situation worse.

“After more than two decades of NAFTA, there’s no question regarding the relationship between the huge rise in agricultural exports to Mexico and the rise in out-migration from rural areas, much of it to the United States,” Carlsen said. “Right now, we have zero net migration from Mexico to the United States as a result mainly. of lower labor demand since the recession. But if more Mexican farmers are displaced by subsidized US imports, that will change.”

Philip Martin, professor emeritus of agricultural and resource economics at UC Davis, said the damage has already been done and was doubtful of a future spike in immigration. “People can only be displaced from [agriculture] once—there are far fewer Mex farmers today,” Martin told TheDC.

President Trump has continued to threaten that the U.S. will pull out of NAFTA if a favorable deal is not reached. Steven Camarota, director of research for the Center for Immigration Studies, urged caution about predictions and said, “I would say that his point we can expect it to have unforeseen consequence. But what they are I am just not sure.”