In a significant decision, the Supreme Court has rejected a settlement between Western states over the management of the Rio Grande river, one of North America's longest rivers. The ruling, which was made in a 5-4 decision, stated that the water-sharing deal between Texas and New Mexico cannot proceed due to lingering concerns from the federal government regarding New Mexico's water usage.

Justice Ketanji Brown Jackson, while reading the majority opinion, emphasized the importance of addressing the United States' concerns over New Mexico's water use on the Rio Grande, which also impacts Colorado. Justices Sonia Sotomayor, Elena Kagan, Brett Kavanaugh, and John Roberts joined in the majority decision, highlighting the crossing of ideological lines.

However, Justice Neil Gorsuch dissented, expressing New Mexico's fears that the federal government's aggressive theory on water distribution could have a devastating impact on the state's economy. In his dissenting opinion, Gorsuch mentioned that the Supreme Court's ruling appears to contradict a century of established water law jurisprudence.

The rejection of the settlement is disappointing to New Mexico's state engineer, Mike Hamman, who believed that collaborative efforts and lasting solutions would stem from the proposed deal. Hamman acknowledged the importance of making aquifers in the Lower Rio Grande region sustainable and expressed his hopes that all parties involved would return to the negotiation table to work towards a new agreement.

While some New Mexico lawmakers had concerns about the settlement, others showed support. Attorney Samantha Barncastle, representing the Elephant Butte Irrigation District, welcomed the ruling and expressed hope that the parties involved would resume discussions to craft a new agreement.

Farmers in southern New Mexico have been heavily reliant on groundwater wells due to drought and climate change, which have resulted in reduced flows and water scarcity in Rio Grande reservoirs. Texas filed a lawsuit, contending that groundwater pumping in New Mexico was reducing the amount of water delivered as part of the interstate compact.

Previously, U.S. Circuit Judge Michael Melloy had deemed the settlement proposal as fair and reasonable, aligned with a long-standing water-sharing agreement. However, the federal government raised objections, citing the lack of specific water capture or use limitations within New Mexico as a primary concern.

The Supreme Court's ruling sends the matter back to the negotiation table, urging Texas, New Mexico, and the federal government to address the pressing issues surrounding the management of the Rio Grande river.