Regional trade agreements have important consequences for developing countries, but the public opinion literature on trade agreements suffers from several shortcomings. Most significant is that studies tend to take a single year as the point of analysis, leaving us uncertain as to how opinion evolves. This study uses polling data to examine Mexicans’ attitudes toward NAFTA over a ten-year period. Results from regression analyses show an association between Mexicans’ support for the United Nations and their support for NAFTA, and a weaker relationship for other types of cues (presidential, the United States), than other studies have found. The data also reveal an association between Donald Trump’s arrival in the presidency and increased support for NAFTA.