Its trade, its security…and its water.

By Vicente Calderón

The scarcity of this precious resource across the U.S.-Mexico border has become yet another flashpoint between the two countries, with farmers on both sides struggling with climate change and a challenging political climate.

Texas producers and lawmakers—mainly Republicans—claim Mexico is failing to meet its obligations under a water-sharing agreement signed in 1944. For months, they've been pressuring their own authorities, who in turn have been pressuring Mexican President Claudia Sheinbaum's government.

Even President Donald Trump has threatened to impose a 5% increase of tariffs and some U.S. politicians want to use the renegotiation of the trade agreement between Canada, Mexico and the United States to secure its water allocations.

Mexico's position remains firm: the country hasn't violated the treaty, though it has accelerated water deliveries by tapping dams never before used for this purpose.

The 1944 Water Treaty established in Article 4 that Mexico must deliver water from six tributary rivers of the Rio Bravo. A minimum of 350,000 acre-feet of water each year, on average, over a five year cycle, totaling a minimum of 1,750,000 acre-feet over the five year period.

More importantly, the treaty incorporates a mechanism for the current conditions, stipulating that "in cases of extraordinary drought, the shortfalls existing at the end of one cycle can be made up in a following cycle."

This provision was updated through Minute 234 in 1969 to clarify the framework for managing water deficits across extended periods when the hydrological situation warrants such adjustments.

Dr. Ismael Aguilar Barajas, a Tecnológico de Monterrey researcher who has spent decades working on binational water policy, backs the Mexican government's stance.

"Mexico is not in default," Aguilar said in a Zoom interview. "According to the treaty, Mexico has another five years to settle the deficit."

What exists now, Aguilar explains, is an accumulated deficit—not an overdue debt. The treaty contemplates extensions when extraordinary conditions like severe droughts occur, allowing more time to make water payments.

While the political pressure is understandable given current U.S.-Mexico tensions, Aguilar argues that technically, there's no violation of the 1944 agreement.

"The issue is that the treaty has been held hostage to this political pressure from the United States," he said.

Aguilar, who has authored several books on water challenges in northern Mexico, views Sheinbaum's response as difficult but smart.

"The very definition of extraordinary drought is up for academic debate," he acknowledged. "But the reality is we've had less rain in recent years, and climate forecasts suggest we'll have even less water ahead. The treaty accounts for that context."

The debate isn't new — but as the drought drags on, it has only grown more volatile.

In April 2025, the Center for U.S.-Mexico Studies at UC San Diego convened experts to examine how climate change, historic droughts, and mounting pressure on shared resources are reshaping border water politics.

Organizers framed the discussion around a stark premise: water is no longer just a natural resource—it's a geopolitical weapon.

Participants, including Aguilar, agreed that despite its age, the 1944 treaty remains one of the best frameworks for managing such a scarce resource.

Stephen Mumme, a Colorado State University professor who joined the discussion, was unequivocal: "Personally, I'm a big supporter of the treaty. I don't think the treaty is the problem. The treaty allows for interpretation. There's very little in it that says something cannot be done."

They agreed on the flexibility of the international accord.

Months after that webinar, Sheinbaum authorized advance deliveries, including water from the San Juan River—which falls outside the 1944 agreement—as political cover with Washington.

As the dry season worsened, so did pressure from north of the border.

"The longer Mexico takes to release the water, the more our farmers will be hurt. Mexico has an obligation to fix this now," President Trump wrote on Truth Social.

Republican Rep. Monica De La Cruz and Democratic Rep. Henry Cuellar introduced the "Predictable and Reliable Water Supply Guarantee Act" in the U.S. Congress, which would impose restrictions on Mexico. U.S. Senators Ted Cruz and John Cornyn filed companion legislation.

De La Cruz declared on X on March 27, 2026: "The Mexican government is in default AGAIN on the 202,000 acre-feet of water they committed to deliver to South Texas. I won't stop until the 1944 Treaty is included in the USMCA."

Russell Boening, president of the Texas Farm Bureau, warned after transfer of water to the north, in the December 2025 agreement.

"This fight is far from over. History has shown that promises alone don't irrigate crops or sustain rural economies. Mexico's failure to deliver water has already cost the Rio Grande Valley its sugar industry", Boening said.

Aguilar warns that accelerating deliveries carries serious consequences on the Mexican side. The water comes from El Cuchillo Dam, the main source for Monterrey—a metro area of over five million people that suffered a severe water crisis in 2022.

"Few people in Monterrey know that water from El Cuchillo has ended up flowing to the United States," he said. "And they don't realize how vulnerable that makes them under these institutional rules."

One of the most contentious changes is the shift from five-year to annual reviews for the water deliveries, which Sheinbaum confirmed. Some see it as caving to Trump. Aguilar disagrees.

"Annual reviews don't necessarily mean Mexico has to deliver water every year," he explained. "It means checking in on conditions annually. That could actually work in Mexico's favor, because five-year cycles are so long that deficits can pile up and become impossible to repay."

Sheinbaum put it this way: "The five-year framework stays in place, but we've agreed to certain review mechanisms. It used to be reviewed every five years, but now we'll review it annually to see where we stand based on that year's rainfall."

Aguilar firmly opposes linking the water treaty to USMCA trade negotiations, as some Texas legislators are insisting to increase the pressure on Mexico.

"That makes no technical sense whatsoever. It's purely political posturing. And it's definitely not in Mexico's best interest to accept that linkage."

On April 29, 2025, Mexico pledged to allocate between 400 and 518 million cubic meters from May through October 2025, drawing from Amistad Dam, six Mexican tributaries of the Rio Grande, the San Juan River on an emergency basis, and the Luis L. León Dam.

The U.S. State Department confirmed that "Mexico committed to take steps to reduce the deficit in Mexican deliveries by the end of the five-year water cycle."

Mexico's Foreign Ministry has maintained that "the country has not violated the 1944 Water Treaty," noting the agreement comes "in a context of extraordinary and unprecedented drought."

Mexican officials have tried to downplay the current situation by pointing out that 2025 actions "are much smaller than what Mexico delivered from 2002 to 2007 during cycle 27," when the country had to cover a two-cycle deficit of 1,639 million cubic meters plus the standard guaranteed volume of 2,158 million cubic meters. (1,329,000 acre-feet plus the 1,750,000 acre-feet)

Beyond cross-border tensions, Aguilar insists Mexico's biggest threat isn't Washington—it's the lack of a coordinated internal national strategy.

The professor applauds the attention President Sheinbaum has devoted to the matter, and notes that "there are significant opportunities to build those domestic agreements that support the design of the best responses."

Chief among the needs is greater funding for the Mexican National Water Commission (CONAGUA), which operates on barely 0.1% of GDP — an extremely low budget for an entity with an increasingly important role in a country facing growing water scarcity in both urban and rural communities.

Agreements among states sharing these river basins remain woefully inadequate.

Sheinbaum laid out her priorities clearly: "Our first objective is ensuring there's no shortage of water for human consumption, obviously. Second, we want to support farmers if they need water for irrigation."

Aguilar thinks his country can rise to the challenge:

"Mexico needs a grand national agreement that brings together the commitments and obligations of all stakeholders. We can't keep waiting for crises to hit. When you're in crisis mode, the window for rational decision-making slams shut."

He also believes another critical institution needs reinforcement. The Comisión Internacional de Límites y Aguas (CILA), Mexico's equivalent of the International Boundaries and Water Commission (IBWC), is also seriously underfunded by the Mexican government, limiting its capacity to fairly resolve bilateral disputes like this one.

The legislative calendar is adding new urgency. With midterm elections coming next November in the U.S., political pressure shows no sign of easing.

Just days ago, on June 1, 2026, Congresswoman De La Cruz announced that H.R. 9053, the Farmers Act, had been formally introduced. The bill would impose tariffs on Mexico if it refuses to comply with the 1944 Water Treaty, with funds collected allocated to South Texas farmers impacted by missed water deliveries, according to the official statement.

Although GovTrack.us gives the bill little chance of advancing, similar efforts to leverage tariffs over water compliance are not isolated.

In the Mexican state of Tamaulipas, farmers' organizations have expressed concern over the recent agreements reached with the United States, arguing that they go beyond what the 1944 treaty established and could have serious consequences for their land and livelihoods.

One thing seems certain: the pressure over water is far from over.