WASHINGTON - A federal appeals court Tuesday cleared the way for Cherokee Freedmen to move forward with a lawsuit that challenges their ouster from the Cherokee Nation of Oklahoma.

The Freedmen claim a right to tribal membership as descendants of Cherokee slaves. The Cherokee booted them from the tribe in a March 2007 vote.

Tuesday's decision by the U.S. Court of Appeals for the District of Columbia clarified that tribal leaders may be subject to lawsuits, even as the Cherokee Nation as an entity is protected from court action.

The Freedmen celebrated the decision, while the Tahlequah-based tribe praised the ruling as an affirmation of the Cherokee's sovereignty.

A lower court will now decide whether U.S. government and Cherokee Nation officials can disregard an 1866 treaty authorizing tribal benefits to freed slaves and their descendants.

"We see this as a full victory, we're excited about this," said Jon Velie, the attorney for the Freedmen group. "The court crafted an opinion that protects both tribal sovereignty and individual Indian rights."

The decision is the latest in a long-running dispute over whether the Freedmen are eligible for tribal benefits. The fight has even reached Congress, where bills have been introduced to force the Cherokee to restore the group's rights or else lose federal grant money.

The ousted Freedmen count 23,000 among their ranks. Tribal courts have temporarily reinstated the group while the lawsuit is pending.

In 2003, the Freedmen sued the U.S. interior secretary because of the federal government's interpretation of the Cherokee's rights under the treaty. When the tribe sought to intervene in the case, the Freedmen added the nation and its officials, including Principal Chief Chad Smith, to the suit.

The three-judge panel reversed a lower court decision that made the tribe a party to the suit.

"This decision is a strong affirmation for tribes across the country, who rely upon federal courts to uphold tribal sovereignty when it comes under attack," Smith said in a statement. "The court once again acknowledged that tribes have inherent sovereignty that predates the founding of the United States, and that tribal sovereign immunity still exists today."

The Cherokee Nation, by a 77 percent margin, voted last year to consider as tribal members only those blood relatives of Indians listed on a century-old registry known as the Dawes Rolls.

The Freedmen seek court relief to bar future Cherokee elections unless the excluded group can participate and run for office.