An increase in domestic manufacturing output and a proportionally greater domestic investment in manufacturing does not necessarily mean an increase in domestic manufacturing jobs; this increase may simply reflect greater automation and higher productivity. Although the U.S. total civilian employment may have grown by almost 15 million in between 1993 and 2001, manufacturing jobs only increased by 476,000 in the same time period. Furthermore from 1994 to 2007, net manufacturing employment has declined by 3,654,000, and during this period several other free trade agreements have been concluded or expanded.
In 2000, U.S. government subsidies to the corn sector totaled $10.1 billion. These subsidies have led to charges of dumping, which jeopardizes Mexican farms and the country's food self-sufficiency.
Other studies reject NAFTA as the force responsible for depressing the incomes of poor corn farmers, citing the trend's existence more than a decade before NAFTA's existence, an increase in maize production after NAFTA went into effect in 1994, and the lack of a measurable impact on the price of Mexican corn due to subsidized corn coming into Mexico from the United States, though they agree that the abolition of U.S. agricultural subsidies would benefit Mexican farmers. According to Graham Purchase in Anarchism and Environmental Survival, NAFTA could cause "the destruction of the ejidos (peasant cooperative village holdings) by corporate interests, and threatens to completely reverse the gains made by rural peoples in the Mexican Revolution."
The preparations for NAFTA included cancellation of Article 27 of Mexico's constitution, the cornerstone of Emiliano Zapata's revolution of 1910--1919. Under the historic Article 27, Indian communal landholdings were protected from sale or privatization. However, this barrier to investment was incompatible with NAFTA. With the removal of Article 27, Indian farmers feared the loss of their remaining lands, and also feared cheap imports (substitutes) from the US. Thus, the Zapatistas labeled NAFTA as a "death sentence" to Indian communities all over Mexico. Then EZLN declared war on the Mexican state on January 1, 1994, the day NAFTA came into force.