– The Constitution is commonly said to protect Americans from double jeopardy — that is, being tried twice for the same crime.

But the Supreme Court on Monday reaffirmed its view that this promise comes with a major exception. Because a state and the federal government are separate "sovereigns," each is free to prosecute a violation of one of its laws, even if they overlap, the court ruled.

The 7-2 decision preserved a rule that allowed federal prosecutors to bring criminal civil rights charges against two Los Angeles police officers who had been acquitted by a state jury in Simi Valley for the beating of motorist Rodney King. These dual prosecutions were also crucial during the civil rights era when federal prosecutors intervened in criminal cases in Southern states.

When the case was argued in December, most of the justices said they were reluctant to overturn the precedent. At issue is a clause in the Fifth Amendment that says "nor shall any person be subject for the same offence to be twice put in jeopardy of life or limb."

Terance Gamble was arrested and prosecuted in Mobile, Ala., for having a loaded handgun in his car. Because he had a previous conviction for robbery, he was charged under a state law for having a gun despite his conviction for a "crime of violence." Federal prosecutors then filed a second charge against him seeking a longer prison term because he was a felon with a weapon.

Gamble appealed the double conviction, but lost. "We have long held that a crime under one sovereign's law is not 'the same offence' as a crime under the laws of another sovereign," said Justice Samuel Alito, speaking for the court. He said the two offenses were usually not the same. For example, federal prosecutors may be acting to protect civil rights while state authorities might have brought a traditional murder or assault prosecution.

He also cited the example of foreign prosecutions. "Imagine, for example, that a U.S. national has been murdered in another country," he said. U.S. prosecutors would gladly try the perpetrator of such a crime, even if he had been acquitted by a local court.

Justices Ruth Bader Ginsburg and Neil Gorsuch filed separate dissents. Gorsuch said the majority had violated fundamental fairness.

"A free society does not allow its government to try the same individual for the same crime until it's happy with the result," he wrote. "Unfortunately, the court today endorses a colossal exception to this ancient rule against double jeopardy."

The decision could affect associates of President Donald Trump accused of wrongdoing and hoping for pardons.

Because Trump's pardon power extends only to federal crimes, the ruling leaves people he pardons subject to state prosecutions.