Trudeau took a political gamble when his government approved the project in 2016 after an environmental review, saying it was in the "national interest" as it would help ease Canada's reliance on the USA market, and get a better price for its crude oil.
He said the government was reviewing the decision "carefully" and considering its next steps and would respond "promptly and in a meaningful way" as the court requested.
August 23, 2018: The Supreme Court dismisses an appeal by the City of Burnaby to reconsider a lower court decision that denied the port city leave to appeal the ruling by the National Energy Board.
Executive Director of the Georgia Strait Alliance Christianne Wilhelmson says the Trudeau Liberals have been shamed.
Taken together, the court decision and approval by KML shareholders to sell the pipeline "are important next steps in getting this project built in the right way for the benefit of all Canadians", Morneau said.
The court decision is a victory for indigenous leaders and environmentalists, who have pledged to do whatever necessary to thwart the pipeline, including chaining themselves to construction equipment.
"Our coast was not considered by the National Energy Board and I feel that those citizens have been vindicated today", said Horgan.
Analysts have said China is eager to get access to Canada's oil, but largely gave up hope that a pipeline to the Pacific Coast would be built.
March 15, 2018: B.C. Supreme Court grants indefinite injunction preventing protesters from coming within five metres of two work sites for the project.
"Four or five hundred tanker crossings a year will not happen, the risk of a diluted bitumen spill will not increase, it's significant to the orcas, it does not solve all the other problems", says Wilhelmson.More news: Aretha Franklin lies in gold-plated open coffin as fans pay respects
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That failure "was so critical that the Governor in Council could not functionally make the kind of assessment of the project's environmental effects and the public interest that the (environmental assessment) legislation requires", says the ruling written by Justice Eleanor Dawson.
Shortly after the court ruling Thursday, company shareholders voted more than 99 per cent in favour of the sale.
The fallout from the court's decision extended to the federal government's strategy to cut greenhouse gas emissions as Alberta Premier Rachel Notley pulled the province out of Ottawa's climate plan.
That exclusion made the NEB report unreliable for the government when assessing the project, the court found.
Tany Yao, UCP MLA for Fort McMurray-Wood Buffalo, said it was premature to call the project dead, but said the court decision was "an insurmountable delay and a result of the bureaucracy of changing the rules on the fly".
Finance Minister Bill Morneau said Thursday the federal government is carefully reviewing the decision but is determined to proceed with the project, that, he said, is in the best national interest and "critically important" for the economy. "Being an equity owner of this project means we will have the voice to do so", he said.
McKay Métis president Ron Quintal said the big lesson from the ruling is that a factor has been identified in "a flawed system that has failed the Indigenous people of this country".
"What seems to me is happening in this case is the court is drifting a little more towards saying, 'We're really going to take a hard look at how you engage in that consultation and sometimes we're going to be so demanding that it's pretty much equivalent to a consent type of rule'". You can nearly hear the sighs of relief from the chief executives of utilities and pension plans across the country, who were all offered a chance to buy into Trans Mountain over the past few years, and who all said no to Kinder Morgan.
Many First Nation groups too have described it as a victory.
October 26, 2017: Kinder Morgan Canada asks NEB to allow work to begin despite a failure to obtain municipal permits from the City of Burnaby.
Vancouver Mayor Gregor Robertson said the decision validates his city's concerns about marine impacts and Indigenous consultation.