In a 5-4 decision issued June 22, the U.S. Supreme Court sided with Colorado, Nevada and Arizona in a dispute with the Navajo Nation over water diversions from the beleaguered Colorado River.

The tribe had sought an assessment of its water needs and a plan to meet them, but Colorado argued that siding with the tribe would undermine existing agreements and disrupt the management of the river, The Associated Press reports.

The federal government argued that a ruling in favor of the Navajo Nation would open federal agencies up to water lawsuits from other tribes, the AP noted.

The ruling resolves a lawsuit filed 20 years ago, when the tribe asserted the federal government failed to live up to treaty terms set in the 1800s to ensure it had a sufficient water supply.

Justice Samuel Alito said during arguments in March the tribe's original reservation was hundreds of miles away from the section of the river it was now seeking water from.

The case was Arizona v. Navajo Nation.

The ruling comes after Colorado, Nevada and Arizona announced an agreement this spring to save at least 3 million acre-feet of water from the drought-stricken river by the end of 2026.