For the United States, trade with Mexico offers many benefits for the economy and dietary quality for American consumers.
Regarding the economic benefits, a recent August 2016 article in the magazine Amber Waves, from the U.S. Department of Agriculture -- by USDA economists Steven Zahniser, Adriana Moreno, and Arturo Ruanova -- emphasizes the contribution of the North American Free Trade Agreement (NAFTA). Gradually, from 1994 to 2008, they write, NAFTA removed tariffs and quotas, while at the same time reconciling rules on both sides of the border about how food safety is protected:
Together, this sweeping trade liberalization and ongoing regulatory cooperation made possible a dramatic increase in U.S.-Mexico agricultural trade.The results included an enormous jump in export sales to Mexico, benefiting U.S. farmers. A chart in the Amber Waves article shows that agricultural trade with Mexico is nearly in balance, with agricultural exports equal to or exceeding imports in most years.
USDA's Foreign Agricultural Service has a page devoted to agricultural exports to Mexico, with statistics, links to agricultural trade offices in Mexico City and Monterrey, and a guide for exporters who seek to do business in Mexico. The top 5 U.S. export industries are dairy ($1.3 billion), pork ($1.3 billion), beef ($1.1 billion), poultry ($1.0 billion), and prepared food ($707 billion). Producers in these industries are important to the U.S. agricultural economy, and they are politically influential.
Like the Amber Waves article, USDA's FAS notes the role of NAFTA in this trade:
Under the North American Free Trade Agreement (NAFTA), Mexico and the United States have eliminated all tariffs and quantitative restrictions on agricultural goods and have strengthened scientific ties to eradicate diseases and pests, conduct research and enhance conservation.Moving beyond just agricultural products, the office of the U.S. Trade Representative (USTR) has a web page devoted just to trade with Mexico. For U.S. producers, Mexico was the second-biggest export market in the world. Total U.S. trade with Mexico is more in balance than trade with several other countries. In 2015, U.S. exports to Mexico were an astonishing $240 billion, almost double our exports to China. Meanwhile, U.S. imports from Mexico were $294 billion, much less than our imports from China. Our trade deficit with Mexico is just $54 billion (much smaller than our deficit with China, Germany, or Japan, for example).
For nutrition, federal government sources place a heavy priority on increased consumption of fruits and vegetables. For example, the Healthy People 2020 initiative lists fruit and vegetable consumption as "Leading Health Indicators" and proposes ambitious goals for increased consumption.
USDA data on food imports show that fruit imports from Mexico increased almost 6-fold from 2000 ($0.8 billion) to 2014 ($4.7 billion). Similarly, vegetable imports from Mexico increased 3-fold from 2000 ($1.7 billion) to 2014 ($5.4 billion). With increased tariffs or reduced trade with Mexico, fruit and vegetable prices in the United States would be much higher. The consequence of reduced agricultural trade with Mexico would be that Mexicans would have more fruits and vegetables (and less beef, pork, and processed food), while U.S. consumers would have less fruits and vegetables (and more beef, pork, and processed food).
I always read with great care the large literature by public interest advocates who raise serious concerns about agricultural trade with Mexico. For example, Tom Philpott at Mother Jones describes conditions for agricultural workers in Mexico as "heartbreaking." Food and Water Watch argues that provisions for sanitary/phytosanitary rules in existing and proposed trade agreements are too weak. I hear the point of each, and yet think that reduced trade is not the remedy. I do not think the workers in Tom's story are helped by shutting down the U.S. Mexico border, and I think Mexico is capable of producing food to the same standards as producers in Florida or California. Looking forward beyond the hardships that excellent public interest sources have noted, we can improve labor and food safety standards without exaggerating differences across the border as if we had our own house fully in order.
In short, U.S.-Mexico trade is important and beneficial to the U.S. economy and nutrition. You can hear this view from me, and (as of this writing) you can hear it from the steady, sober online data sources maintained by the federal government.