WASHINGTON - The Supreme Court was told Wednesday that Congress overstepped its bounds by allowing Indian tribes to prosecute nonmembers under tribal law after the justices had removed that right in a 1990 court ruling.

In lively arguments over the future of Indian sovereignty, Alexander Reichert of Grand Forks, N.D., said his client, Billy Jo Lara, was the victim of an invalid law that Congress had no power to pass.

"This was done under the color of authority," Reichert told the justices, "and my client was punished for it."

Lara, a member of the Turtle Mountain Band of Chippewa in North Dakota, pleaded guilty in a Spirit Lake Nation tribal court after punching a tribal officer who was trying to arrest him. But because the tribal officer also was a federal officer, Lara also was indicted in a North Dakota federal district court.

Reichert said the Spirit Lake Nation tribe, also of North Dakota, had no sovereign right to try Lara initially because Congress improperly gave it the authority to do so. The conviction of Lara means that a second trial would violate his Fifth Amendment protections against double jeopardy.

Attorneys for the U.S. government countered Wednesday that Congress had every right to "define the contours" of Indian sovereignty. Deputy Solicitor General Edwin Kneedler told the justices that legislators were trying to fill gaps in jurisdiction left by the 1990 Supreme Court ruling when they amended the Indian Civil Rights Act to allow Indian tribes to prosecute nonmember Indians. Congress was acting on its historical right to regulate relations between tribes, he said.

The justices' ruling in Lara's case, expected by July, will settle important and difficult questions over tribal criminal jurisdiction. The 8th Circuit Court of Appeals ruled in Lara's favor, saying Congress' power didn't extend far enough to rewrite a court ruling about Indian affairs. The 9th Circuit Court of Appeals, in a different case, said Congress did have that right. The two circuits encompass most of the states with significant Indian populations.

The justices' decision will also confront a more common dispute at the high court: the separation of powers between Congress and the court.

Under Chief Justice William H. Rehnquist, the court has embarked on significant reviews of congressional authority and many times asserted its supremacy in interpreting the law. At the most basic level, Congress' attempt to specifically undo the 1990 court ruling with legislation is a direct challenge to the court's authority. The justices typically haven't responded favorably to such aggressive congressional behavior.

On Wednesday, justices appeared split over Lara's case and the validity of Congress' action.

Some, including Justice Antonin Scalia, appeared uncomfortable with the idea of Congress being able to decide who is subject to tribal law. He and Rehnquist wondered whether the government would suggest that Congress could decide that Indian sovereignty extended even further to subject non-Indians to tribal law.

"If that's what you're suggesting," he told Kneedler, "I'd say that's a step I'm not prepared to contemplate. If your proposal would raise those kinds of serious constitutional questions, then I'd say we're less inclined to accept it."

Justice David Souter was concerned that the government was asking the justices to rewrite the idea of dependent sovereignty - a doctrine that permits Indian tribes to govern their affairs but not reach beyond their borders to govern other matters.

"The very concept of dependent sovereignty is inconsistent with tribal jurisdiction over a nonmember," Souter said. "If we stick with that concept, then they can't have that power. We said it's gone by virtue of sovereignty."

Kneedler argued that the court, in the 1990 ruling, limited tribal power to deal with crimes committed by nonmembers, but Congress lifted those limits and was within its right to do so.

Some justices questioned what would happen to Lara if they ruled in his favor. If the court invalidated his initial plea deal, then he wouldn't be at risk of double jeopardy from a federal charge, they suggested.

Reichert said that wouldn't be a fair way of interpreting the ruling.

"He was punished for this, and he was in jail for this already, under the color of authority," Reichert said. That punishment, which can't be erased, is what the Fifth Amendment says can't be imposed a second time, he said.

"The government cannot rewrite the log of the jail," Reichert said. "He was in there."