The Wampanoag Tribe of Gay Head (Aquinnah) has vowed to go to federal court if necessary to win the right to build a casino, after Gov. Deval Patrick rebuffed the tribe’s attempt to come to the negotiating table last week.

Claiming the state has the right to regulate gambling on Indian lands, an attorney for the governor wrote in a letter that the Vineyard tribe waived its sovereignty more than 20 years ago when it signed a settlement agreement. But the tribe contends that federal Indian gaming law trumps state law.

The tribe is competing for one of three state casino licenses reserved for an Indian tribe, working against a July 31 deadline to reach an agreement with the governor. The governor is already in negotiations with the Mashpee Wampanoags, who unveiled detailed plans yesterday for a $500 million casino in Taunton.

“It has been the position of the commonwealth for over a decade that the [tribe’s] land claims settlement act . . . and related settlement agreement, acknowledges, preserves and protects the commonwealth’s authority to regulate gaming both on the Aquinnah’s land in Gay Head and on any after-acquired land within Massachusetts,” wrote Jerome Levine, an attorney with Holland and Knight in Los Angeles, in an April 20 letter to the Vineyard tribe’s attorney. “As such, we have not been authorized to begin compact negotiations at this time.”

The letter was widely seen as a blow to the efforts by the Vineyard Wampanoags to build a casino, but in a statement issued yesterday, tribal chairman Cheryl Andrews-Maltais said the tribe still sees plenty of room for negotiation. “We do not interpret the letter as stating the governor refuses to negotiate,” Mrs. Andrews-Maltais wrote in an e-mail to the Gazette. “We remain willing and able to negotiate a compact.”

A meeting was held on Tuesday this week between attorneys for the tribe and the state. “Our attorneys had frank and constructive discussions during the meeting . . . We are hopeful that formal negotiations will commence immediately,” Mrs. Andrews-Maltais wrote.

A spokesman for the state housing and economic development office, which is overseeing the new state gaming law, said yesterday that the governor has no desire to pit one tribe against another. “We are not interested in picking winners and losers,” said communications director Jason Lefferts. “It has been the commonwealth’s position that the two tribes are in fundamentally different situations under state law.”

A state law allowing casinos, passed late last year, set up a short timeline that required tribes to identify and if necessary buy land, gain community approval for a casino and negotiate license terms with the state. The Vineyard Wampanoags put in a formal request in March with Governor Patrick to begin negotiations. The governor requested more information, and a series of letters followed. There are three parcels of land under consideration by the tribe to build a casino; in Lakeville, Freetown and Fall River. Referendum votes have been scheduled in all three towns for May, and meetings with local officials to unveil financial backers are scheduled for the coming weeks.

In a purchase and sale agreement sent to the state on April 17 and obtained by the Gazette, the purchase price for two parcels totalling 514 acres of land in the towns of Lakeville and Freetown is $15 million.

Two weeks ago the tribe announced through a new Web site plans to possibly build a casino on land it owns in trust in Aquinnah. The chairman of the Aquinnah selectman has asked town counsel Ronald H. Rappaport for an opinion on whether this would be allowed. Mr. Rappaport said he believes the landmark 2004 state Supreme Judicial Court case that found the tribe had waived part of its sovereignty when it signed a settlement agreement with the town and is bound to follow state and local zoning laws, means a casino cannot be built on trust lands in Aquinnah.

Meanwhile, there are sharply differing views of the extent to which the state can control gaming on tribal land in Aquinnah and other land the tribe may acquire on the mainland. The dispute is based on different interpretations of the 1983 settlement agreement that led to federal recognition of the tribe, as well as federal Indian law and court cases involving other tribes.

The contrary views first surfaced in 1997, when the tribe was pursuing an ultimately unsuccessful effort to develop a casino in Fall River. After the Massachusetts attorney general’s office issued an opinion that the state had the right to regulate or even prohibit gambling on land the tribe acquired after 1983, a lawyer for the U.S. Interior Department issued a contradictory opinion. Responding to a request from the tribe for guidance, the Interior Department concluded in 1997 that the tribe would be eligible to conduct gaming on tribal lands outside of Aquinnah, provided that it otherwise followed the requirements of the federal Indian Gaming Regulatory Act (IGRA).

Because the two opinions were focused on the potential for a casino in Fall River, neither specifically addresses the tribe’s right to build a casino on existing tribal lands on the Vineyard, but even the Interior Department’s opinion, which is otherwise favorable to the tribe, suggests that it could not.

In her e-mail Mrs. Andrews-Maltais highlights this dispute and underscores the tribe’s intention to challenge the matter at the federal level, even when it comes to the tribe’s rights on the Vineyard. “IGRA, not state law, governs gaming on Aquinnah’s existing trust lands,” she wrote.

She also wrote: “If the governor refuses to negotiate, IGRA provides for specific remedies that we will pursue in federal court.”