While Prime Minister Justin Trudeau is widely believed to have put an end to Enbridge’s controversial Northern Gateway pipeline by mandating a ban on tanker traffic on British Columbia’s north coast, Globe and Mail reporter Gary Mason says the path ahead may be more complicated than it seems.

Support for the project from participating Aboriginal groups could run headlong into Trudeau’s “solemn promise to confer with First Nations on just about everything,” Mason writes. The ban could also face challenges from U.S. shippers, and from Enbridge itself.

“Enbridge has said Aboriginal communities stand to share $1 billion if the project goes ahead,” he notes. “So far, 28 bands have signed equity agreements giving them a 10% share in the profits, among other incentives. The company is expected to soon announce it has reached equity accords with 10 or more other groups.” So while some First Nations are challenging the project in court, others support it.

Meanwhile, the United States maintains it has freedom to navigate along the B.C. coast, and “any measure that hinders American oil supplies from reaching communities in the Alaska panhandle is not going to make our U.S. neighbours happy.” And Enbridge, after spending more than C$500 million on the project, “will rightly want to be reimbursed for the money it invested in this endeavour before the rules were changed.”

In the end, Mason writes, “the federal government may well end up making good on its promise to ensure the Northern Gateway pipeline never gets built. But it will not be a quick or easy process, nor an inexpensive one. Killing this pipeline could cost Ottawa north of a billion dollars—and months, if not years, in court.”