• President Trump threatens a 5% tariff on Mexican imports unless Mexico releases water owed under a 1944 treaty.

• The dispute centers on an alleged shortfall of hundreds of thousands of acre-feet of Rio Grande water destined for Texas.

• Texas farmers face significant agricultural challenges due to the water shortage, impacting crops and livestock.

• The 1944 treaty governs shared water resources but lacks strict enforcement mechanisms for non-compliance.

• The confrontation raises questions about balancing trade policy, international agreements and domestic agricultural needs.

In a move that intertwines trade policy, agricultural security and a decades-old international agreement, President Donald Trump has threatened to impose a 5% tariff on all imports from Mexico. The ultimatum, issued in early December 2025, is not over immigration or drug trafficking, but water. The president demands that Mexico immediately release hundreds of thousands of acre-feet of Rio Grande water owed to the United States under a 1944 treaty, citing severe harm to the Texas agricultural industry. This confrontation revives a perennial cross-border dispute, placing the vital needs of American farmers at the center of a high-stakes international negotiation.

The roots of the dispute: The 1944 Water Treaty

The current crisis is framed by the U.S.-Mexico Water Treaty of 1944, a complex pact designed to manage shared resources from the Colorado River and the Rio Grande. For the segment of the Rio Grande that forms the border, the treaty stipulates that Mexico must deliver to the United States a minimum average of 350,000 acre-feet of water per year from six specified Mexican tributaries, amounting to 1.75 million acre-feet over each five-year cycle. In return, the U.S. has obligations to Mexico from the Colorado River.