Developers of a proposed Nantucket Sound wind farm were cleared to move forward Tuesday when Massachusetts' high court rejected a claim that the project sidestepped local opposition to win a key permit.

Cape Wind project, a 130-turbine proposal that would be the nation's first offshore wind farm, was given permission last year by a state board to build power transmission lines through state waters. The Supreme Judicial Court backed that decision in a 4-2 ruling.

Cape Wind had gone to the state after a local board, the Cape Cod Commission, rejected in 2007 its request to build about 18 miles of undersea and underground transmission cables to connect to the regional electric power grid. The local board said Cape Wind hadn't provided sufficient information.

Opponents argued the state exceeded its powers and was trumped by the local ruling, but the court disagreed. It said that that interpretation would mean the state Energy Facilities Siting Board's authority applied everywhere but Cape Cod.

Cape Wind opponents also argued the state board was wrong to consider only the transmission lines' effect on Massachusetts, rather than the entire project's effect. But the court said that doing so would have essentially given the board the power to kill a project under federal jurisdiction.