In this episode of the Planet Money podcast, we explore the 26-year journey of American potato farmers trying to break into the Mexican market. Starting with the initial hope brought by NAFTA, the story unfolds through challenges posed by the Mexican potato lobby, which leveraged pest concerns as a trade barrier. A notable example is the "potato DMZ," a 16-mile stretch where American potatoes were initially banned. Ultimately, this podcast reveals how intricate trade regulations can transform into politicized tools that protect local industries, showcasing the complexities within the realm of international free trade.