By Sabrina Shankman for Inside Climate Change - Hundreds of miles from the nearest oil field or fracking well, the answer to this question is playing out here, as a longrunning David-and-Goliath battle over plans to pipe tar sands oil from Canada to Maine for export nears a pivotal moment. On one side is South Portland, a picturesque waterfront city of 25,000, which approved an ordinance in 2014 to outlaw heavy crude exports from its harbor in an overwhelming City Council vote. On the other is the Portland Pipe Line Corporation, the company behind the project, and its allies, including the American Petroleum Institute, whose members include most major oil and gas companies. API spent hundreds of thousands of dollars to defeat a ballot measure in 2013 that would have blocked the project. The City Council approved the ordinance a year later. The Portland Pipe Line Corporation is now suing the city, with support from API and the U.S. Chamber of Commerce, arguing the ban was unconstitutional. A federal judge is expected to rule in the coming weeks. A decision in favor of the company could effectively open a gateway for the flow of carbon-heavy tar sands oil to one of the East Coast's largest oil ports. For other cities seeking to restrict oil and gas activities, South Portland's four-year fight to fend off the oil industry offers perhaps a cautionary tale.