The U.S. and Mexico have fought a war, so it’s probably not fair to say that cross-border relations are at an all-time low.
But they’re certainly fraying as President Donald Trump pursues his mass deportation agenda and withdraws from international commitments.
And yet, there remains an arena where the two countries have repeatedly found common ground — or rather, water — at least for now.
Mexico will use less Colorado River water over the next two years as part of an agreement with the U.S. government to help Arizona, California and Nevada shoulder the burden of a sweeping megadrought and record-low elevations in the river’s biggest reservoirs.
The deal shows some rare cooperative spirit at a time when the institutions that (attempt to) govern the river are themselves under historic stress — and when U.S.-Mexico relations aren’t so hot, either.
Mexico will accept 250,000 fewer acre-feet of Colorado River water per year than its legal allocation, a contribution that will help soften the blow of sweeping federal cuts to the three Lower Basin states.
“This Minute makes sure water is shared fairly among our users and protects the health of the Colorado River during these difficult times,” said Chad McIntosh, Commissioner of the U.S. Section of the International Boundary and Water Commission — more on that in a second — in a press release.
The seven U.S. states of the basin, the federal government, dozens of Native American tribes, irrigation districts and other users of Colorado River water spent the last three years attempting to develop new plans for sharing the river’s water after current agreements expire at the end of this year. They largely ended up at each other’s throats.
The downriver states formed a unified front and drew up their own shortage sharing plan. But without agreement from all seven states, the federal government is implementing its own plan, one that requires 1.25 million acre-feet in annual cuts from Arizona, California and Nevada over the next two years. (That sum is basically what the three states had already offered to cut, but bigger reductions could be coming after the next two years.)
U.S. IBWC Commissioner Chad McIntosh and Mexican IBWC Commissioner Adriana Reséndez shake hands after signing Minute 334 in El Paso, Texas, on September 2, 2026. (Courtesy USIBWC)
Mexico, as part of the newly announced agreement, will contribute to that 1.25 million acre-feet total. The two countries will consult on possible further reductions if reservoir conditions continue to deteriorate and on higher deliveries if (knock on wood, but don’t count on it) reservoir conditions improve.
The agreement has some other important components, too, like a pilot program to reduce the river’s salinity as its water enters Mexico and a commitment of $5 million for habitat restoration in the Colorado River delta. It also expands Mexico’s ability to bank water in Lake Mead, a boon to Mexico and to reservoir elevations, at least in the short term. Remember when we told you that conservation pools might be the future?
"The more water users that share in Colorado River water shortages, the less the burden of those shortages on any one user, sector, or geography,” wrote Audobon Society Colorado River program director Jennifer Pitt last week.
A wandering border
Rivers are essential to the relationship between the U.S. and Mexico, and to the definition of the border itself.
If you’ll entertain a parroted history lesson: The 1848 Treaty of Guadalupe Hidalgo, which ended the Mexican-American War, delineated a boundary that followed parts of both the Rio Grande and Gila River. The 1854 Gadsden Purchase extended that border west of the Rio Grande and south of the Gila.
Rivers, however, tend to resist such rigidity, and as they meandered, so too did the border — a farm or community on one side of the river might eventually end up on the other. So the treaties developed temporary commissions to adjudicate boundary disputes. These bodies were formalized as the International Boundary and Water Commission in 1889, meaning that the U.S. and Mexico have had a formal hydro-diplomatic relationship for longer than the U.S. Bureau of Reclamation, for example, has existed.
It’s a relationship with a sometimes rocky history punctuated by bright spots of cooperation. Both countries have had issues with water deliveries and water quality. Colorado River water that reached Mexico was too salty, killing crops south of the border. Sewage and wastewater from tributaries in the Tijuana River valley, meanwhile, were flowing into California.
Under a 1944 treaty, Mexico would receive 1.5 million acre-feet of Colorado River water a year from the U.S., and the U.S. would receive 350,000 acre-feet a year of Rio Grande water from Mexico. The treaty also led to the development of dams, desalination and pollution controls along the rivers, though water quality issues persist.
But drought in the 1990s has left Mexico often unable to deliver that Rio Grande water, and it’s accumulated a so-called water debt as a result. While the country was able to reduce that debt in the 2000s, the "megadrought" of the 2020s has exacerbated its delivery issues, with farmers on both sides of the border running out of water. For its part, Mexico has agreed to take Colorado River reductions on multiple occasions.
A case for more meetings
Throughout all this, the two countries have repeatedly reached new agreements, even as river users within the U.S. itself have found themselves increasingly at odds — and even as U.S. domestic and foreign policy has antagonized Mexico and Mexican Americans.
“They’ve been very cooperative over the years and through many administrations,” said Terry Goddard, the chair of the Central Arizona Project board. “We’ve been blessed that the water discussions have, through all of the SB1070 craziness, all of the immigration issues, managed to maintain a very professional, non-jingoistic approach to collaborative water policy.”
That spirit may be faltering in the Trump administration, however. Mexico’s reduced Rio Grande deliveries have hung farmers in south Texas out to dry, and in his second term, Trump responded by threatening to withhold aid and impose sanctions. He also rejected Mexico’s request for a small allocation of Colorado River water normally earmarked for drought-stricken Tijuana, the first instance of such a refusal in the age of the 1944 treaty.
For more evidence, look to the U.S. government’s page for the IBWC, which reiterates in multiple instances that the commission “protects Americans from Mexican sewage,” which “is flowing across our border and onto our beaches.” Remind you of anything?
So, for reasons that are at once the same and opposite, the 1944 agreement is controversial in both countries. The same drought threatens farmers in the Rio Grande Valley on both sides of the border. But it at least seems like the commission has proved to be remarkably resilient in the face of these challenges.
“I really believe that there's a model there that has a lot to provide for U.S.-Mexico relations in other realms,” Carlos de La Parra, managing partner of the Luken Center for Strategies on Water and Environment, told KJZZ’s Alex Hager.
And hell, maybe there’s a model for water management within the boundaries of the U.S.
As Goddard noted, the perennially-at-odds Upper and Lower divisions of the Colorado River basin have conceptually agreed to mediation, which, in a way, is what the IBWC offers to the U.S. and Mexico. But formal negotiation structures might be a hard sell to the seven states.
“I don’t know if the states would ever give up their authority,” Goddard said.
As a case in point — the Upper Basin actually does have a commission: the Upper Colorado River Commission. But when it comes down to negotiations, the states send their own representatives, not commission delegates.
“The commission, they’re not the ones at the table to deal with,” Goddard said.
Much ado about Knuth-ing: Lawyers for Cochise County Supervisor Tom Crosby, who was indicted for delaying the certification of election results in 2022, say the lead investigator on the case is a liar, Kiera Riley reports for Capitol Media Services. The Arizona Attorney General investigator, William Knuth, resigned in January after an internal affairs report said he provided false documentation in a police report and inaccurately reported his work hours. Crosby’s lawyers are hoping a transcript of a grand jury proceeding in an unrelated case will show Knuth has a habit of being less than honest. Knuth was also involved in the fake electors case that was thrown out, and became a target of Turning Point Action’s Tyler Bowyer.
Building a pipeline: As Tucson officials try to fix the homelessness situation, they're looking for more places in the city to build shelters, Mia Kortight reports for the Sentinel. To make that happen, they're planning to change zoning rules and parking restrictions, as well as partner with nonprofits. City residents are going to have a lot to say about that, so officials are holding three events over the next month to get feedback from the public. As it stands, most of the places where shelters are allowed to be built are on the outskirts of town and usually far from public transportation, officials told KGUN’s Vanessa Gongora.
As local as it gets: Voters in the Amphi Public School District are going to decide in November whether to allow the sale of four buildings that used to house elementary schools, JJ McKinney reports for KGUN. District officials say selling the buildings would save money on maintaining them and generate cash that could be used at schools that are still open. State law requires school districts to get approval from voters before selling buildings. One wrinkle in the plan is the fact that the Arizona State School for the Deaf and Blind relocated to one of the buildings earlier this year.
Been around the block: Former state lawmaker Matt Kopec is the new intergovernmental affairs manager at Pima County, per a memo from County Administrator Jan Lesher. Kopec has built up quite a résumé since he was appointed to a state House seat in 2016. He worked as an aide to former Tucson Councilwoman Karin Uhlich, spent more than four years at the county health department and has been on the Amphi Public School District Governing Board for eight years. The position Kopec is taking was created by the Pima County Board of Supervisors in March.
Just a reminder: We depend almost entirely on financial support from readers to keep the Agenda going.
That could get awkward: U.S. Customs and Border Protection’s preferred site for a new Border Patrol station is adjacent to Elgin Elementary School in Sonoita, per Dave Lumia at the Patagonia Regional Times. Nothing is finalized yet, and CBP has an alternative site that would basically expand its existing station that’s nowhere near the school. As Lumia points out, the expansion is part of establishing a much larger Border Patrol footprint in Southern Arizona, including a new facility near Three Points and expanding the checkpoint on Interstate 19 near Tubac.
Today, we’re taking a cue from Sports Illustrated’s “This week’s sign that the apocalypse is upon us.”
People are betting on the race in Congressional District 6 on the Kalshi prediction market. So far, it looks like about $34,000 is on the line (along with, you know, democracy and whatnot).
We can’t tell which is more apocalyptic: people betting on elections or the ungodly amount of money each candidate has raised for their campaigns so far.
