Supreme Court weighs Navajo Nation's water rights in Colorado River dispute.

The Navajo Nation has been fighting for access to water from the lower Colorado River for over 20 years, with almost a third of its population lacking access to clean, reliable drinking water. The U.S. Supreme Court heard arguments on Monday over the tribe's water rights, with the federal government arguing that it represents tribal interests in water disputes. The court must decide how far the government's responsibilities go in reserving the tribe's right to water. A favorable ruling would allow the tribe's legal efforts around the Colorado River and other waterways to move forward.