BOSTON — An Indian tribe seeking to build a resort casino in southeastern Massachusetts is hoping a critical decision on its tribal reservation application is imminent.

The Mashpee Wampanoag tribe, whose ancestors negotiated peace with the Pilgrims, suggests a U.S. District Court ruling from earlier this month bodes well for its chances.

Tribal Council Chairman Cedric Cromwell says the Dec. 12 opinion, dealing with the Cowlitz tribe in Washington state, “gives hope to tribes throughout all Indian country” seeking to regain control of tribal lands.

He said the ruling affirms that the federal government can take land into trust for tribes that were “under federal jurisdiction” in 1934, but not necessarily federally recognized.

The tribe, which won federal recognition in 2007 after a 30-year quest, has proposed a $500 million casino in an industrial park in Taunton.

It has submitted an application to the federal Bureau of Indian Affairs to designate about 150 acres in Taunton and about 170 acres in the Cape Cod town of Mashpee as its tribal reservation.

Nedra Darling, a spokeswoman for the Bureau of Indian Affairs, says the agency is still reviewing the Mashpee’s application, which was initially filed in 2012. “There is no specific time frame for a decision at this time,” she said.

Clyde Barrow, a University of Texas-Pan American professor and casino gambling expert, said among the questions federal authorities must weigh is whether the tribe has ancestral and contemporary ties to the Taunton land and whether the Mashpee were under federal jurisdiction by 1934, the year Congress passed the Indian Reorganization Act.

The tribe has said Taunton and the region that surrounds it are historically and culturally significant. A majority of the tribe’s 2,600 members live outside the town of Mashpee. Many are in the Fall River-New Bedford region.