WASHINGTON — In a victory for the Mashpee Wampanoag Tribe in its yearslong battle for sovereignty, a federal judge has ruled the Interior Department incorrectly applied its own guidelines in finding the tribe did not qualify for land-in-trust status.

U.S. District Judge Paul Friedman found that the department’s 2018 decision that the tribe was not under federal jurisdiction in 1934 was “arbitrary, capricious, an abuse of discretion and contrary to law.”