Tens of thousands of Mexican farmers took to the streets last week to protest Nafta’s scheduled phasing out of the last tariffs on agricultural items traded between Mexico and the United States. At the same time that farmers are claiming that Nafta is killing their incomes, a New York Times Op-Ed argues that Nafta actually helps Mexican farms. In the case of corn, the piece claims that the three-fold increase in US corn imports into Mexico since Nafta has not competed with Mexican corn production because the import varieties have mostly been agricultural feed types, not the edible white corn produced by Mexican small scale farmers. In short, Mexican corn farmers are not directly competing with US corn, and have in fact benefited under Nafta from a 30 percent increase in corn production.

A large and unanswered question lies at the heart of the differing views of Nafta—and of the impact of free trade in general. Similar to the contradictory studies on the positive or negative impact of foreign aid, it is extremely difficult in today’s globalized, complex economies to separate causes and correlations. While it is true that the US corn that Mexico imports is not directly competing with peasant farmers, the fact remains that the prices received by farmers in Mexico has fallen by roughly 70 percent since Nafta was implemented. At the same time, the cost of tortillas and corn flour sold in Mexican grocery stores has increased dramatically. There are plenty of possible causes for this dynamic that have nothing to do with Nafta—such as US corn priced long-term below cost on the world market—but common sense dictates that there is still some relation.

That relationship seems to lie somewhere within the challenge of implementing free trade agreements that are also fair. Part of fair trade requires that producers on both sides of an agreement are taking the full costs of production into account. The objections from many in the US to Nafta and other agreements are couched in terms of lax labor and environmental standards in other countries. But as a paper by Alejandro Nadal from the Colegio de Mexico and Timothy Wise from Tufts University shows, the US is can be just as guilty of exporting environmental degradation and unfair practices. Nadal and Wise show that the majority of US corn is grown with the help of modified high-yield seed varieties, large amounts of chemical inputs and, of course, subsidies which hide the real cost of production. In contrast, most of the 18 million Mexicans employed in the Mexican corn production industry work on small farms on which they grow maize from seeds that they preserve from their own crops and from the exchange of seeds with neighbors. Few use significant amounts of chemicals or mechanized farming practices or industrial irrigation. As for subsidies, the Mexican government does give them, but at levels that were a third of US subsidies prior to Nafta and have decreased in the years since. Furthermore, Mexican corn subsidies go mainly to large producers in the north of the country. Mexico has also decreased the amount of subsidies it pays, in contrast to the US which has increased its payments by billions of dollars since the US 1996 Freedom to Farm was passed. The price of US corn is artificially low not only because of subsidies, however, but also because the environmental costs of chemical run-off and seed variety loss is not factored into the commodity price. Likewise, Mexican grower prices do not include credit for the stewardship of crop diversity or for practices which preserve the environment. Thus the least common denominator practices – and prices – get transferred.

The simultaneity of market changes—declining and growing industries, falling prices, freer trade, environmental degradation, automation, outsourcing, globalization—are largely responsible for a growing tide of anti-free trade sentiment that is increasingly showing up in the United States putting free trade agreements with Colombia and Panama at risk. As the article points out, opposition to the Colombian free trade agreement on these grounds is especially hard to explain given that the agreement is mainly lowering Colombian trade barriers (Colombian exports to the US are largely duty-free already).

Free trade’s role as a global anti-poverty catalyst is too often ignored. The global decline in absolute poverty has largely centered on rising incomes in China and India, which in turn have been primarily driven by free trade and globalization. Last summer, economist Tyler Cowen highlighted a paper which shows that the more globalized parts of the Mexican economy have benefited the most from Nafta—to put it another way, the more globalization the better. Indeed those Mexican sectors that have benefited are increasingly concerned about the anti-Nafta rhetoric.

Economist Benjamin Friedman’s excellent book The Moral Consequences of Economic Growth illustrates how in times of economic uncertainty societies become increasingly inward-focused and xenophobic. Given the current state of the global economy it’s unsurprising that the forces opposing free trade are becoming more vocal and more powerful. The challenge for policymakers is to steer a middle course which emphasizes both freer and fairer trade and recognizes the global anti-poverty benefits of lowered trade barriers. Within a sector such as corn, with its dramatically artificial pricing mechanisms and its dramatic asymmetries in production, the cost of ignoring fair in favor of free creates enormous negative consequences for the disadvantaged within the trading group.