Mexico is ready to hit the U.S. where it hurts: Corn. Mexico is one of the top buyers of American corn in the world today. And Mexican senator Armando Rios Piter, who leads a congressional committee on foreign relations, says he will introduce a bill this week where Mexico will buy corn from Brazil and Argentina instead of the United States. It's one of the first signs of potential concrete action from Mexico in response to President Trump's threats against the country.America is also the world's largest producer and exporter of corn. American corn shipments to Mexico have catapulted since NAFTA, a free trade deal signed between Mexico, America and Canada.Rios Piter's bill is another sign of Mexico's willingness to respond to Trump's threats. Trump wants to make Mexico pay for a wall on the border, and he's threatened taxes on Mexican imports ranging from 20% to 35%.