Texas v. New Mexico
The Supreme Court blocked Texas and New Mexico from finalizing a negotiated Rio Grande water-sharing settlement, ruling that the federal government's separate legal claims about New Mexico's groundwater pumping could not be eliminated without its agreement.
The decision means the states must keep litigating alongside the federal government, which argues that groundwater pumping in New Mexico violates the interstate water compact at a level the proposed settlement would have quietly accepted as lawful.
“we cannot now allow Texas and New Mexico to leave the United States up the river without a paddle.”
The majority's closing line explaining why the federal government cannot be cut out of the settlement against its will.
How it got here: Texas sued New Mexico directly in the Supreme Court in 2013; after partial trial before a Special Master, the two states proposed a consent decree that the federal government then challenged by filing an exception.
The Case in Depth
What happened
Texas, New Mexico, and Colorado share the waters of the Rio Grande through a 1938 interstate agreement called the Rio Grande Compact. Texas sued New Mexico in 2013, claiming that rising groundwater pumping in southern New Mexico was diverting water that should reach Texas. The federal government joined the suit because it operates the federal irrigation system that delivers water to districts in both states and must fulfill a 1906 treaty obligation to deliver water to Mexico. After years of litigation and partial trial, Texas and New Mexico negotiated a consent decree, but the federal government refused to agree, arguing the settlement would legalize the very pumping it claims violates the Compact.
The question before the Court
When Texas and New Mexico settle their decade-long Rio Grande water dispute, can the federal government block the settlement because it would erase the government's own claims in the case?
The Court's answer
No — parties settling a lawsuit cannot use a consent decree to eliminate the valid legal claims of a participant who has not agreed to the settlement. The Court ruled that the federal government has its own distinct legal interests in the Rio Grande Compact, stemming from its role operating the federal irrigation project, its contractual obligations to deliver water to districts in both states, and its 1906 treaty duty to deliver water to Mexico. Those interests were recognized in the Court's 2018 decision permitting the government to join the case, and they remain valid today.
The proposed settlement would have introduced a new water-measurement formula built on data from a period of elevated groundwater pumping, effectively treating that level of pumping as consistent with the Compact. That is precisely what the federal government argues violates the Compact. Approving the decree would therefore bar the government from pressing that argument, and a court cannot enter a consent judgment that disposes of the government's claims without its actual consent.
Curious how the Court got there? See the step-by-step legal reasoning →
Why it matters
Water users and communities in southern New Mexico and the El Paso area who were counting on the settlement to bring legal certainty to Rio Grande water distribution now face continued court proceedings with no clear end date. The ruling also signals that states settling river-sharing disputes will have less flexibility to reach a final agreement if the federal government has joined the lawsuit and holds its own legal claims.
What changes now
The proposed consent decree is blocked and the case returns to the Special Master for further proceedings, with the federal government remaining as a party. The underlying dispute — whether New Mexico's groundwater pumping violates the Rio Grande Compact — still has not been decided on its merits and awaits trial. The case has already been in litigation for more than a decade, and no settlement can take effect without the federal government's agreement.
What this does not decide
The Court expressly left open whether the federal government could have initiated its own Rio Grande Compact lawsuit if no state suit had been pending, and whether it can expand the scope of this lawsuit. The Court also did not decide whether New Mexico's groundwater pumping actually violates the Compact — that merits question remains for further proceedings.
Concurrences and dissents
Dissent — Justice Gorsuch
The dissent would have approved the consent decree, arguing it is consistent with the Compact and gives the federal government everything it originally sought when it joined the case — protection of treaty water deliveries to Mexico and continued use of the D2 Period baseline it has employed for over 40 years. The dissent contends the 2018 Texas I ruling never established that the government has independent Compact claims of its own, but only permitted it to participate to protect specific federal interests now satisfied by the settlement. Any remaining claims the government believes it holds, the dissent argues, can and should be pursued in lower courts, consistent with a century of water law precedent deferring to state authority over water rights.
How the Court got there
The legal reasoning, step by step
- The governing rule comes from two prior decisions: Firefighters v. Cleveland (1986) held that settling parties cannot use a consent decree to dispose of a non-consenting intervenor's valid claims, and United States v. Ward Baking Co. (1964) held that a court may not enter a consent judgment without the government's actual consent when the government seeks relief it may be entitled to at trial. Both rules apply here.
- The threshold question is whether the federal government has valid claims under the Rio Grande Compact. The Court found the answer already established in its 2018 Texas I ruling, which permitted the government to intervene because it has 'distinctively federal interests' in the Compact's operation — specifically its duties under contracts to deliver water to New Mexico and Texas water districts, its integral role running the Rio Grande irrigation project, and its treaty obligation to supply water to Mexico.
- The States argued the federal government has no valid Compact claims because it does not itself receive an allocation of water under the Compact, and because the government never specifically pleaded a demand to return pumping to 1938 levels. The Court rejected both arguments as foreclosed by the 2018 decision: the government lacked a water allocation then too, and what matters is that both Texas and the government pleaded that New Mexico was pumping more groundwater than the Compact permits — regardless of the precise terminology used.
- On whether the consent decree would actually dispose of the government's claims, the States themselves had conceded before the Special Master that the decree would 'resolv[e] all of the Compact claims stated by any party.' The decree's centerpiece — a new formula (the EEPI) measuring compliance using 1951–1978 data, a period when groundwater pumping was already elevated — would embed those higher pumping levels as Compact-compliant, the very result the federal government argues is a Compact violation.
- The States argued the government could pursue its claims in a lower-court forum instead. The Court rejected this because the government's claim is that the Compact itself bars New Mexico's current pumping rates. The consent decree would settle that question definitively by deeming those rates compliant with the Compact, leaving no other forum in which the government could argue the Compact forbids them.
Doctrinal impact
Cases affected by this decision
Reaffirms Texas v. New Mexico (583 U.S. 407)
The 2018 ruling permitting federal intervention compels the conclusion that the U.S. has valid Compact claims today.
Reaffirms Firefighters v. Cleveland (478 U.S. 501)
Settling parties still cannot use a consent decree to dispose of a non-consenting intervenor's valid claims.
Reaffirms United States v. Ward Baking Co. (376 U.S. 327)
A court may not enter a consent judgment without the government's actual consent when the government seeks triable relief.