The US Supreme Court has thrown another obstacle in the path of the Mashpee Wampanoag and other tribes seeking to develop casinos under federal law, by expanding the number of people who can file lawsuits to challenge the gambling developments.

Exposing tribal projects to more litigation could cause years of delay, increase costs for developers, and potentially make it more difficult and expensive to get financ­ing for tribal casinos, ­specialists say.

“What the decision could do is erect new barriers for tribes and heighten those that already exist,” said Steven Light, codirector of the Institute for the Study of Tribal Gaming Law and Policy at the University of North Dakota. He said the high court decision, released Monday, has sent ripples of concern through the country’s Native American tribes.

The Mashpee Wampanoag are pursuing a casino in Taunton, following a federal approval process created by Congress for federally recognized tribes.

The longstanding challenge for the Mashpee, as for many tribes, is that tribal gambling can only occur on sovereign ­Indian land. Tribes can buy land like any other organization, but they must persuade the US Department of the ­Interior to take the land into trust on behalf of the tribe, in order to make the land eligible for a tribal casino. The most prominent nearby examples of tribal casinos are Foxwoods and Mohegan Sun in Connecticut.

‘Because it multiplies the number of people who can challenge, it multiplies the likelihood of delay due to such challenges, and therefore the cost.’

Historically, the federal government has moved very slowly in approving land-in-trust appli­cations, often taking years.

That process was further hampered by a 2009 Supreme Court ruling that threw into question whether the federal government can take land into trust for tribes recently recognized by the federal government. That ruling — which ­decided a Rhode Island-based case pitting Donald Carcieri, then governor, against the Narragansett tribe — held that the Department of the Interior can only take land into trust for tribes that were “under federal jurisdiction” when Congress ­enacted the 1934 Indian Reorganization Act.

Since the so-called Carcieri ruling, Native American tribes and their supporters have sought a federal law to clarify the government’s power to take land into trust, but the gridlocked Congress has not acted.

The Supreme Court added a new wrinkle Monday, voting 8 to 1 to allow a lawsuit to go forward challenging a land-in-trust decision for a Michigan tribe, the Match-E-Be-Nash-She-Wish Band of Pottawatomi Indians, also known as the Gun Lake Tribe. The lawsuit was filed by a neighbor, David Patchak, who opposes a casino on the land. Patchak argues that the federal government could not legally take the land into trust because the Gun Lake Tribe was not recognized in 1934.

Experts are still parsing the latest ruling, but it appears to open the door for nearly any neighbor to challenge a land-in-trust decision.

“Traditionally, local sovereigns like municipalities were allowed to file those challenges, but individuals were not,” said Robert Clinton, a tribal law specialist at Arizona State University. “This ruling allows individuals to sue.

“Because it multiplies the number of people who can challenge, it multiplies the likelihood of delay due to such challenges and therefore the cost,” he said.

The ruling also sets a precedent for allowing challenges to be filed as late as six years from the decision, said professor Matthew L.M. Fletcher, a specialist in tribal law at Michigan State University.

Just the threat of litigation looming over a project could raise borrowing costs and delay construction, he said. An opponent could, in theory, delay a project six years by threatening to sue, then file at the last minute and tie the project up in court for years more.

“And [tribes] might end up losing,” said Fletcher. “These Carcieri-type cases have really never been litigated before. They’re going to be cases involv­ing a lot of historical ­research and expert witnesses and documents. Those kinds of cases are really uncertain.”

The Mashpee tribe was not formally recognized by the federal government until 2007, ­after a long lobbying campaign. Despite the Carcieri case, the tribe has been pursuing a land-in-trust application for its proposed Taunton casino site, ­under the argument that the Mashpee can demonstrate long connections to the federal government that will satisfy require­ments of the Carcieri ­decision.

Cedric Cromwell, the Mashpee Wampanoag tribal chairman, said in a statement that the court’s latest ruling “does not change anything about our pursuit of land in trust, which is progressing rapidly, nor does it change our focus on bringing thousands of jobs and millions in revenue to our tribe, Taunton, and Southeastern Massachusetts through our destination resort casino in Taunton.”

The tribe is currently negotiating with Governor Deval ­Patrick over the amount of money the casino would pay to the state and how the facility would be regulated. These agreements, known as compacts, are key milestones in the federal approval process.

Patrick’s administration said Tuesday that the talks will continue.

“Hypothetical legal action in the future, which has always been a possibility, will not cause us to pause or reframe our ongoing compact negotiations with the Mashpee tribe,” said Jason Lefferts, spokesman for the state Executive Office of Housing and Economic Development.