SOUTH PORTLAND, Maine—A federal judge has handed a win to South Portland, Maine over a pipeline company that wants to send tar sands oil through the city, a proposal seen as opening a path for Canada’s crude to reach the East Coast for export.  

But the fight is not over. A federal district court judge dismissed on Dec. 29 all but one of the company’s claims against the city. The ruling still leaves open a key question: whether the city is violating the U.S. Constitution by blocking the project.

At the heart of the lawsuit is the question of local control and what—if anything—a community can do to block an unwanted energy project.

The outcome could influence similar lawsuits elsewhere. When the Portland Pipe Line Corporation (PPLC) sued this small coastal city in 2015, it had some powerful allies, including the American Petroleum Institute, whose members include most major oil and gas companies.

The industry argued that a local ordinance prohibiting the export of heavy crude from South Portland’s harbor is unconstitutional. That ordinance essentially stopped in its tracks PPLC’s plans to reverse an existing pipeline and start piping tar sands oil from Canada to Maine, where it could be shipped to international markets.

“It’s a great decision,” said Sean Mahoney, of the Conservation Law Foundation, who has advised the city. “They won on 8 out of 9 counts—but they’ve got a big kahuna count left.”