The 23-year-old North American Free Trade Agreement (NAFTA) is due for some updates, a Mexican trade official said last week in a meeting with Iowa Farm Bureau leaders. But any revised agreement should build on strong gains the United States and Mexico have made in agricultural trade, said Ken­neth Smith Ramos, director of the NAFTA office in the Mexican Embassy in Washington, D.C.

"We need to build on the success we’ve had over the years," Ramos told the Iowans on the Iowa Farm Bureau Federation national policy trip. "This is not the time to erect barriers. That would be a slippery slope to protectionism, which would hurt everyone."

Ramos urged his Iowa...