Two Maine Indian tribes have asked the nation’s highest court to resolve a dispute with paper companies about water-quality regulation they say cuts to the heart of tribal sovereignty.

The petition filed with the U.S. Supreme Court late Wednesday is the tribes’ last legal recourse in a battle that so far has gone in the paper companies’ favor.

“The issues at stake are at the core of federal Indian affairs,” Kaighn Smith, attorney for the Penobscot and Passamaquoddy tribes, said Thursday.

For that reason, he said there is “a stronger than average chance” the high court, which takes only a small fraction of the cases presented to it, will choose to hear this matter.

“This is big. This is very important,” said Smith, who works for Drummond, Woodsum & MacMahon in Portland.

The case arose last year when three paper companies asked the tribes for all their documents relating to water-quality regulation. The companies – Great Northern Paper Inc., Georgia-Pacific Corp. and Champion International Corp. – made the request after the tribes contested the state’s application to the U.S. government to issue federal wastewater discharge permits.

The U.S. Environmental Protection Agency last month granted Maine’s request to issue federal permits in all of the state except “Indian country.” It has asked the U.S. Department of Justice to help it decide what to do in this area. The Penobscot Reservation, near Old Town, includes islands in the Penobscot River. The Passamaquoddys have two reservations in eastern Washington County.

The tribes have said they want the federal government to retain permitting authority in waters near their lands because the state is too beholden to the paper companies.

The tribes refused to turn over the documents and the companies sued, claiming they are entitled to the papers under the Maine Freedom of Access law. The tribes said the access law, which says government agencies must make their meetings and documents available to the public, does not apply to them.

Superior Court Judge Robert Crowley disagreed and, in November, sentenced three tribal governors to jail and assessed fines of $1,000 a day against the tribes until the documents were turned over or his opinion was appealed.

The tribes appealed to the Maine Supreme Judicial Court, which ruled in May the tribes must turn over most of the documents sought by the companies.

The court ruled the tribes are subject to Maine’s Freedom of Access Act in most instances and must turn over to the paper companies any correspondence between them and state and federal government entities.

Minutes of tribal council meetings are internal documents and don’t need to be turned over, the court ruled. The judges told the Androscoggin County Superior Court to decide what happens to documents that don’t fit into either of these categories, such as correspondence between tribes and between tribal officials and consultants regarding water quality.

The tribes appealed to the 1st Circuit Court of Appeals in Boston to reverse the ruling. The federal court upheld the state rulings, so the tribes petitioned the Maine Supreme Judicial Court to reconsider its ruling and to postpone the proceedings in the lower state court to give the tribes a chance to appeal to the U.S. Supreme Court. The Maine high court denied that request.

The Maine Supreme Court ruling “mandated the entry of hostile corporations onto [the tribes’] reservations and stripped [the tribes] of their governmental prerogative to decide if, and under what terms, the non-Indian public should have access to tribal property,” the tribes said in the 30-page petition to the nation’s highest court Wednesday.

The Maine court did this by construing the congressionally approved 1980 Maine Indian Land Claims Settlement Act as having relegated the tribes to the same status as municipal governments, the petition said.

Although attorneys for the paper companies argue this is in fact what the settlement act did, tribal governors disagree.

“It was supposed to protect our sovereignty,” Penobscot Nation Governor Barry Dana said earlier this week.

He recently spoke with members of his nation who negotiated the settlement act, and they told him they in no way agreed to limit the tribes’ sovereignty, Dana said. He and the other governors view having to share documents that relate to tribal government as an invasion of that sovereignty.

The high court could decide as early as October whether to hear the case.

While the tribes pursue their case with the U.S. Supreme Court, proceedings in state court are moving forward. Superior Court Justice Crowley will hold a hearing early next month to decide how to proceed in the contempt-of-court proceeding.

At that level, the paper companies have pressed ahead with their claims to view the documents in question, while the state Attorney General’s Office has said it supports the tribes’ request to have the matter delayed while awaiting action from the U.S. Supreme Court.

While the tribes’ legal options are running out, the Penobscot Nation has enlisted the help of a New Jersey congressman. Rep. Frank Pallone visited the nation earlier this month to tour Indian Island and meet with Gov. Dana.

He said he would consider federal legislation to help resolve the issue if that is necessary.

Pallone is the senior Democrat on the subcommittee on the environment and hazardous materials of the House Commerce Committee, as well as the House Resources Committee, which has jurisdiction over American Indian issues.