RIVERTON, Wyo. (AP) _ Representatives of Wyoming tribes and a national group dedicated to ending tribal sovereignty held a lively but civil debate over a boundary dispute involving the state, a federal agency and the tribes.

The Citizens Equal Rights Alliance was holding a conference in Riverton this weekend despite objections from some tribal members who question the group’s intentions.

The group came to Riverton because of a dispute over a U.S. Environmental Protection Agency decision saying that lands around Riverton are legally Indian country. Wyoming is challenging the EPA’s decision, which granted a request from the Northern Arapaho and Eastern Shoshone tribes to treat their joint Wind River Indian Reservation as a separate state under the federal Clean Air Act.

During a meeting Friday with government officials and the media, members of the alliance encouraged local leaders to stand up to the EPA and urged them to fight for the state’s constitutional rights, the Casper Star-Tribune reported (http://bit.ly/1hYkNjL ).

“Our enemy is the federal government, in terms of being able to overreach like this,” said Lana Marcussen, the group’s legal adviser.

Officials from the Eastern Shoshone and Northern Arapaho tribes voiced their side at the meeting.

Shoshone Business Council Chairman Darwin St. Clair Jr. said expressing different opinions is essential to moving forward in solving the boundary dispute.

“I know not everyone has read up on Indian law,” he said. “I hope that people who are presenting this information are presenting it in the right context. A lot of times, especially with legal opinions, you can read it however you would like in your interpretation. As humans, we may have different interpretations, and that’s OK, too, but that’s where the question lies.”

Citizens Equal Rights Alliance board members and city managers from across the country also decried what they consider federal overreach in Indian policy in general.

Treating Indian reservations as sovereign states is unconstitutional, board member Elaine Willman said.

“It is a de facto creation of a state within a state,” Willman said. “If I were going to be treated equally with someone here, we would be treated similarly without intruding on each other’s lives. Treatment as states replaces state authority, and that’s the conflict.”