Central Maine Power’s parent company has won out in a battle over the planned construction of a $1 billion transmission project.

On Thursday, Maine’s Supreme Judicial Court ruled that a ballot initiative aimed at stopping the project is unconstitutional.

Avangrid, CMP’s parent company, filed a suit against the Maine Secretary of State’s Office in May, claiming that the initiative violated a separation of powers provision in Maine’s constitution. The court sided with that argument, stating that the initiative “exceeds the scope of the people’s legislative powers” conferred by the Maine Constitution.

The NO CMP Corridor campaign issued a response, saying they are weighing all legal options on how best to proceed.

Avangrid also put out a statement, saying the ruling is “a victory for the state of Maine and our future, both environmentally and economically.”

The corridor would run through Maine and deliver hydropower from Canada to the New England power grid.