The approval was given by Prime Minister Justin Trudeau's government in 2016, who announced plans to purchase the pipeline and expansion project for $4.5 billion this spring.
The outcome was not in question as Kinder Morgan Inc. retained about 70 per cent of the shares after spinning off its Canadian assets in a $1.75-billion initial public offering in May of 2017.
Like a sports team riding an improbable winning streak, the Trans Mountain pipeline's run of 16 straight legal victories ended in stunning fashion Thursday when the Federal Court of Appeal quashed the federal government's approval of the project.
"Canada failed in Phase III to engage, dialogue meaningfully and grapple with the real concerns of the Indigenous applicants so as to explore possible accommodation of those concerns", the decision reads.
The Squamish Nation cheered the ruling as a recognition of Indigenous rights.
Even with the court decision, Morneau said the project is in the national interest and needs to go ahead.
The court ruling "is an incredible blow, especially with the government on the hook for buying it", said Nelson Wiseman, a political science professor at the University of Toronto.
Lee Spahan, chief of the Coldwater First Nation in the Nicola Valley - which he said is known as the people of the creek - said the ruling helps save water.
"It shows Canada might not be as open for business as we thought it is", he says.
Finance Minister Bill Morneau said in a tweet that the federal government is reviewing the decision.
Stewart Phillip, the grand chief of the Union of British Columbia Indian Chiefs, said the ruling took him aback.
"That's exactly the problem, there wasn't meaningful consultation and so these are the kinds of things that need to be done the next time around".
Taylor said the pipeline and its associated infrastructure are likely to have impacts on many species, but because of the popularity of killer whales, they tend to act as a "flare" for numerous issues associated with the project.
That exclusion made the NEB report unreliable for the government when assessing the project, the court found.
The decision also hurts Canada's oil producers, who say the expanded pipeline is needed to address bottlenecks that have sharply reduced prices for their crude.
"The government should never have bought this pipeline", he said.
Speaking at a short press conference in Victoria, Horgan said the case has always been about First Nations rights and the assertion by the Tsleil-Waututh "that the [National Energy Board] process was flawed and did not take into consideration their rights and title". In return, the federal government has committed to piping Alberta's oilsands bitumen to British Columbia's coast, where it can be shipped to overseas markets.
Back in 2013, shortly after he was first elected Liberal leader, Trudeau headed to the Calgary Petroleum Club, where he accused Stephen Harper's Conservative government of needlessly antagonizing environmentalists and First Nations with an unabashedly pro-energy industry stance that resulted in no new major pipelines being built.
That allowed it to claim there were no "significant adverse environmental effects", a conclusion that was central to its report.
The province's lawyer said Ottawa's decision to approve the pipeline's expansion between Edmonton and Metro Vancouver was based on a broad base of evidence that considered environmental, economic and Indigenous interests. The city of Burnaby unsuccessfully pushed the Supreme Court to stop the project.
Vancouver Mayor Gregor Robertson said the decision validates his city's concerns about marine impacts and Indigenous consultation.
In fact, increased tanker traffic poses a threat to endangered Southern resident killer whales, the court found. The court decision does not affect Canada's purchase of the project from Kinder Morgan, Anderson said in his statement.
The court ruled that the energy board review contained a fatal flaw: it excluded the project's impact on marine shipping.