The Wampanoag Tribe of Gay Head (Aquinnah) has no authority to build a casino on the Vineyard under state or federal law, town counsel Ronald H. Rappaport said in an opinion this week.

The opinion was requested by the chairman of the Aquinnah selectmen three weeks ago, following an announcement by the tribe that it would consider some kind of casino operation on the Vineyard as it scrambles to compete for one of three state gambling licenses expected to be issued in the coming months.

“The simple answer to the question is no,” Mr. Rappaport wrote in the seven-page opinion addressed to Aquinnah selectman and board chairman James Newman.

The Mashpee Wampanoags, the only other federally recognized tribe in the commonwealth, are already in negotiations with Gov. Deval Patrick for a license to build a $500 million casino in Taunton.

The governor’s office has to date declined to negotiate with the Vineyard tribe, citing a 1983 land claims settlement agreement where the tribe partly waived its sovereignty. The tribe has responded that it will go to federal court if necessary to assert its right to build a casino under the Indian Gaming Regulatory Act. And the tribe is pressing ahead with its own plans — a purchase and sale agreement has been signed for two parcels of land totalling 514 acres in the towns of Lakeville and Freetown, and meet-and-greet sessions are planned in those communities next week. Referendum votes on the casino question will be held on May 29 in Freetown and June 2 in Lakeville.

There are many complicated questions of law surrounding the casino question for the Vineyard Wampanoags, and Mr. Rappaport’s opinion focuses specifically on whether a casino would be permitted on land the tribe owns in Aquinnah. He found at every turn that it would not.

The opinion recounts the history of the 1983 settlement agreement, which dates to 1974 when the tribe was not yet recognized by the federal government as a Native American tribe. The tribe sued the town of Gay Head (now named Aquinnah), claiming that it had violated the Indian Non-Intercourse Act, an old law uncovered by a Maine attorney governing the transfer of Indian lands. A negotiation followed between the town and the tribe that lasted for nearly 10 years. In 1983 the tribe and the town settled the litigation in a joint agreement. Among other things the agreement provided for the transfer of certain lands in the town to the tribe, now known as the settlement lands. The settlement lands were eventually transferred to the federal government to be held in trust for the tribe, after it achieved federal recognition in 1987.

The 1983 settlement agreement later was incorporated into state and federal legislation.

And the agreement is now at the center of every issue involving the tribe and its quest to become involved in some kind of casino venture in Massachusetts.

In his opinion, Mr. Rappaport said he found plain evidence that both the state and federal acts barred the tribe from building a casino in Aquinnah.

The state legislation included a land use plan for the settlement lands, and expressly noted that they were subject to the zoning regulations in effect in 1983.

“The town’s zoning bylaw, as of that date, does not allow a casino, gambling facility or other gaming activities as permissible uses,” Mr. Rappaport wrote.

And the federal legislation contained a provision which said that any land owned by an Indian tribe in Gay Head would be subject to state and local laws, “including those laws . . . which prohibit or regulate the conduct of bingo or any other game of chance,” the town attorney wrote.

Mr. Rappaport also recounted the events that began in 1999 when the settlement agreement was tested in court for the first time, after the tribe built a shed on its land fronting Menemsha Pond without obtaining a building permit. The landmark case around the small shed was argued all the way to the state Supreme Judicial Court, which in 2004 upheld the settlement agreement and found that the tribe was bound to follow state and local zoning laws. A key issue in the case was whether the tribe had partly waived its sovereign immunity; the court found that it had.

The sovereign immunity waiver was cited by attorneys for Governor Patrick in a recent letter declining to negotiate with the tribe. But Cheryl Andrews-Maltais, chairman of the Vineyard tribe, countered that the federal Indian Gaming Regulatory Act (IGRA), adopted in 1988, trumps state law and gives the Island Wampanoags the right to build a casino.

In his opinion Mr. Rappaport disagreed, although only with respect to Aquinnah. Mr. Rappaport detailed another opinion requested by the tribe in 1997 from the assistant secretary for Indian Affairs on the subject. The assistant secretary “concluded that the IGRA did not supersede the settlement agreement . . . and that the tribe could not conduct gaming in Aquinnah,” Mr. Rappaport wrote. “The gravamen of the opinion is that the tribe enjoys the ability, under the IGRA, to seek gaming operations elsewhere in the commonwealth, but not in Aquinnah (then Gay Head).”

Mr. Rappaport underscored the fact that his opinion focuses narrowly on the question of a possible casino in Aquinnah.

“I express no opinion as to whether the settlement agreement . . . would preclude the tribe from conducting gaming activities elsewhere in the commonwealth,” he wrote. “It is clear that the tribe has no right to seek any gaming rights under the IGRA in Aquinnah.”

The Aquinnah selectmen did not comment on the opinion at their regular meeting this week. Mr. Newman said later that he asked for the opinion as a protection measure for the town.

“I think we asked for it in order to have our bases covered, so we know where we stand. That’s the only reason it was requested,” he said.

Mrs. Andrews-Maltais could not be reached for comment. A communications consultant to the tribe said that Mr. Rappaport’s letter is under review. “Our lawyers are looking at the letter and we will have more to say very soon,” said Jim McManus of Slowey McManus Communications in Boston.