The United States Supreme Court said it would not intervene in a tri-state water dispute between Alabama, Florida and Georgia that until a year ago threatened to severely restrict the Atlanta area’s access to its main water supply for roughly three million people.

The decision to stay out of the long-running legal feud means that an appeals decision favorable to the metro Atlanta area will stand, a situation bound to frustrate authorities in Florida, Alabama and even southern Georgia who complain Atlanta uses too much water upstream at the expense of wildlife, fisheries and people downstream on the Chattahoochee River.

That river basin serves multiple states.

From Atlanta, the Chattahoochee flows south, running along the border of Alabama and Georgia.

It merges with the Flint River at the Florida border and becomes the Apalachicola River, which cuts south across the Florida Panhandle and empties into the Gulf of Mexico.

Communities in Alabama and Florida have argued that Atlanta has no legal right to take water from Lake Lanier, a federal reservoir on the Chattahoochee that sits northeast of the city, and that Atlanta’s water usage harms fisheries and drinking water supplies downstream.

In 2009, U.S. District Court Judge Paul Magnuson ruled against Atlanta and signed an order that would have severely restricted the city’s withdrawals from the reservoir to levels last seen in the 1970s — when the city was a fraction of its current size — unless the political leaders of Alabama, Florida and Georgia struck a deal ending the impasse.

No deal has been struck.

Last year, the 11th U.S. Circuit Court of Appeals overturned the looming water cutoff and found that Atlanta had a claim to water from the reservoir. The court instructed the U.S. Army Corps of Engineers to determine how much water the city can use.

ARIZONA IMMIGRATION LAW

On Monday, justices also struck down key parts of Arizona’s immigration law — but not the provision requiring police to check the immigration status of someone they suspect is in the United States illegally.

Even there, though, the justices said the provision could face additional legal challenges.

And while upholding the “show me your papers” requirement for now, the justices took the teeth out of it — by prohibiting police officers from arresting people on minor immigration charges.

The ruling was unanimous in allowing the status check to go forward. But the court was divided on striking down the other provisions.

The provisions that were struck down include one that required all immigrants to obtain or carry immigration registration papers.

Also rejected was a provision making it a state criminal offense for an illegal immigrant to seek work or hold a job.

And the justices said police can’t arrest suspected illegal immigrants without warrants.

The Obama administration had sued to block the Arizona law soon after it was enacted two years ago.

Five other states have adopted variations on the law. Parts of those were on hold pending the outcome of this case.

Justices Antonin Scalia and Clarence Thomas said they would have allowed all of the challenged provisions to take effect.

In Arizona, Governor Jan Brewer called the Supreme Court’s decision a victory for all Americans and said the heart of the law can now be enacted.

Brewer says law enforcement that use the law to violate a person’s civil rights will be held accountable.

Nevada Senator Harry Reid said after Monday’s decision that the high court was right to strike down most of Arizona’s immigration law, which President Barack Obama and many Democrats say is unconstitutional.

But Reid said he is concerned that the high court upheld one provision that requires police to check immigration papers of people they stop for other violations.

That, Reid said predicted, “will lead to a system of racial profiling.”

CAMPAIGN SPENDING, JUVENILE JUSTICE

Justices reaffirmed the Supreme Court’s two-year-old decision relaxing limits on corporate campaign spending and reversed a Montana court ruling upholding state restrictions.

By a 5-4 vote, the court’s conservative justices said the decision in the Citizens United case in 2010 applies to state campaign finance laws and guarantees corporate and labor union interests the right to spend freely to advocate for or against candidates for state and local offices.

The majority turned away pleas from the court’s liberal justices to give a full hearing to the case because massive campaign spending since the January 2010 ruling has called into question some of its underpinnings.

The Supreme Court also said it was unconstitutional for states to pass laws that automatically sentence juveniles to life in prison without parole for murder.

Monday’s 5-4 decision is in line with others the court has made, including ruling out the death penalty for juveniles and life without parole for young people whose crimes did not involve killing.

The decision came in the robbery and murder cases of Evan Miller and Kuntrell Jackson, who were 14 when they were convicted.

Miller was convicted of killing a man in Alabama. Jackson was convicted of being an accomplice in an Arkansas robbery that ended in murder.

A decision on the Patient Protection and Affordable Care Act was expected later this week.

– Alex Sanz and the Associated Press contributed to this report

Tags | Alex Sanz, campaign finance, immigration, juvenile, Supreme Court, U.S. Supreme Court, water