On March 5, Justice Neil Gorsuch delivered the opinion of a unanimous Supreme Court in the case of Texas v. New Mexico. The case stems from the Rio Grande Compact, signed by New Mexico, Texas, Colorado, and the United States in 1938 to resolve their conflicts over water rights from the river. The compact states that Colorado must provide a certain amount of water annually to New Mexico at the border and that New Mexico must then also deliver a certain amount of water annually into the Elephant Butte Reservoir. Texas brought the action against New Mexico, claiming that New Mexico is allowing downstream users in the state to siphon water below the reservoir, which Texas alleges was not anticipated in the Compact. The United States sought to intervene in the lawsuit alleging that since the Reservoir is a Bureau of Reclamation Project, the U.S. has an interest in the case in calculating diversion amounts, and that the US has an agreement to deliver water to Mexico and therefore needs to address any interference with the release of that water.

The case went before a Special Master. The Special Master made three recommendations. First, he recommended that the Supreme Court deny New Mexico’s motion to dismiss Texas’ suit. Second, he recommended that the Supreme Court dismiss the United States’ Complaint in Intervention because it fails to state a claim under the Compact and instead suggested that the Supreme Court should extend its original jurisdiction under 28 U.S.C. § 1251(b)(2) and resolve the claims alleged in the Intervention for reasons of judicial economy and interstate and international nature of the project. Lastly, he recommended that the Supreme Court deny the motions of irrigation districts to intervene.

The opinion of the Supreme Court focused on the narrow issue of whether the United States could intervene by making essentially the same claims that Texas did. In the end, the Court determined that the United States can intervene. The opinion traced the negotiations between the United States and Mexico over water rights culminating in a 1906 treaty between the countries in which the U.S. agreed to deliver an annual amount of water after the construction of a new reservoir.  The opinion then traced the negotiations the U.S. undertook with the states to agree to the Compact, which itself noted that it would not interfere with the U.S. obligation to deliver water to Mexico. The Court reasoned that the “Compact is inextricably intertwined with the Rio Grande Project and the Downstream Contracts.”  The Compact is intended to have an equitable apportionment of the waters of the Rio Grande and the reason it is able to do so is because of the downstream contracts that the U.S. negotiated and approved. Through these downstream contracts that ensure delivery of water to Texas, the U.S. can be considered an agent of the Compact, ensuring that Texas gets its equitable share since the water deposited by New Mexico is in the reservoir 100 miles from the border. The Court also reasoned that New Mexico noted both in pleadings and during argument that the U.S. is an integral part of the Compact, to the extent that one of the States could sue the U.S. if it interfered in the delivery of water in any way. Third, since a breach of the Compact could lead to the U.S. defaulting on its obligations under a Treaty, the U.S. must be allowed to proceed. The Court also considered the fact that the U.S. was making a claim in an existing action, not bringing its own action. Taking all of the factors together, the Court decided that the United States could pursue its claims in the action and referred the case back to the Special Master for further proceedings.