Why the wall was built

This episode of 'America in Pursuit' explores the origins of the U.S.-Mexico border wall through the story of Ambos Nogales, a twin city split by the international boundary. The episode traces how the border evolved from a largely porous line in the 19th century—where towns like Nogales, Arizona and Nogales, Mexico thrived on cross-border commerce and movement—into a heavily fortified zone. The turning point came in 1918, when a violent clash erupted after a Mexican carpenter was ordered to stop for inspection by U.S. customs officials. The resulting Battle of Ambos Nogales, which left over 100 Mexicans and four Americans dead, prompted officials on both sides to demand a physical barrier. The first U.S.-built fence was constructed not as a tool of exclusion, but as a joint effort to demarcate territory and prevent future conflict. The episode reveals how the modern border wall is rooted in a complex history of war, revolution, and shifting anxieties—particularly around espionage during World War I and revolutionary instability in Mexico—rather than immigration control, which only became a central concern decades later. It also highlights how today’s border infrastructure, including the $170 billion 'One Big Beautiful Bill Act' of 2025, builds on foundations laid in the early 20th century. The episode challenges the narrative that the border wall is a new or purely political construct, showing instead that the first walls were born out of practicality and crisis, not xenophobia. It underscores the irony that the fence was initially seen as a way to improve neighborly relations—echoing Robert Frost’s idea that 'good fences make good neighbors'—rather than as a symbol of division. By examining the historical context, the episode reframes the border wall not as a singular policy but as a product of evolving national security concerns, economic interests, and geopolitical instability. The story of Ambos Nogales serves as a microcosm of how borders are not just lines on a map, but living, contested spaces shaped by power, fear, and human connection.