The U.S. Supreme Court will let stand a lower court ruling that threatens Georgia's long-term water plans for the Atlanta region.

The court's decision Monday raises fundamental questions about Georgia's rights to Lake Lanier, a massive federal reservoir outside Atlanta. It could also play a key role in deciding the long-running water wars among Georgia, Northwest Florida and Alabama.

The case involves a 2003 water-sharing agreement with the Army Corps of Engineers that would have allowed Georgia to take far more water from Lanier for drinking water.

Florida and Alabama contested the pact. A lower court agreed, saying the Corps didn't have authority to use the lake for that reason.

Georgia had appealed to the Supreme Court for another review.