President Donald Trump threatened an additional 5% tariff on Mexican imports on December 8, 2025, accusing Mexico of violating the 1944 Water Treaty by withholding over 800,000 acre-feet of Rio Grande water owed to the U.S. every five years, severely impacting Texas farmers' crops and livestock. In a Truth Social post, Trump demanded Mexico release 200,000 acre-feet by December 31 with more soon after, warning: "I have authorised documentation to impose a 5% Tariff on Mexico if this water isn't released, IMMEDIATELY".
The standoff revives April tensions, where Trump eyed tariffs/sanctions; a brief April 28 accord faltered as U.S. lawmakers decried shortfalls despite Mexico's claims of compliance via reservoirs. Under the treaty, Mexico delivers 1.75 million acre-feet per cycle while receiving 1.5 million annually from the U.S., but droughts exacerbate deficits.
Texas agriculture bears the brunt amid prior tariff hikes (25-30% on Mexico/Canada); Mexico faces pressure from its farmers too. No immediate response from Mexico City.