British Columbia's legal defeat on the Trans Mountain pipeline expansion is a disappointing blow for many in the province, but called a "humiliation" by others who think it shouldn't be in court in the first place.

The Supreme Court of Canada unanimously dismissed B.C.'s appeal of a previous lower court decision quashing provincial legislation designed to block the project on Thursday.

"It's obviously a disappointing decision," said Attorney-General David Eby minutes after the ruling.

The decision by the country's highest court strikes down amendments to provincial environmental law drafted by the B.C. NDP government that would have all but banned shipments of heavy oil through interprovincial pipelines.

"Caring about our land and water and our economy, and the impacts of potential spills of not just bitumen but potentially other substances that the province wanted to regulate, is critically important," Eby said.

"We'll certainly be doing what we can within our jurisdiction to protect our economy and our environment."

'Dismissal speaks for itself'

The amendments would have required companies transporting these substances through B.C. to obtain provincial permits.

B.C. argued that, since the province would bear the brunt of damage from any spill, it should control what flows through the pipelines.

The current route of the Trans Mountain pipeline. The expansion would twin it.

The court ruled, however, that provincial permits overstep the constitutional authority of Ottawa — essentially, that B.C. cannot enact legislation on a matter that falls under federal jurisdiction.

"We haven't changed our view of the risks that this transport of heavy oil poses to British Columbians," said George Heyman, B.C.'s environment minister, in an interview Friday on CBC's The Early Edition.

"We are not trying to frustrate or play games. We are trying to do our job," added the minister.

According to Heyman, the price tag to the province for pursuing the case in Supreme Court was about $1 million for outside legal counsel.

Premier John Horgan had promised in the 2017 election campaign "to use every tool in our tool box to stop" the construction of the Trans Mountain expansion.

But B.C. Liberal leader Andrew Wilkinson says it's time for the B.C. NDP to get behind the project and accused the government of wasting time and money on court cases.

"The dismissal speaks for itself," he told Gloria Macarenko, host of CBC's On The Coast.

"When is this government going to learn that the government of British Columbia is subject to the laws of Canada?"

Wilkinson says taking the argument to the B.C. Court of Appeal cost taxpayers $1 million in legal fees in a "futile gesture" that was overturned five to zero.

"[B.C.] then took that to the Supreme Court of Canada and lost nine-nothing with an immediate dismissal from the bench," said Wilkinson.

"It's a humiliation for everybody involved."

'These are political decisions'

Sonia Furstenau, deputy leader of the B.C. Green Party and MLA for Cowichan Valley, argued that the Trans Mountain pipeline expansion is, at the end of the day, a political minefield.

The last time there was significant public backlash against the Trans Mountain pipeline expansion in 2018, thousands protested and about 150 people were arrested. In 2014, there were encampments on Burnaby Mountain and more than 100 people were arrested.

"These are political decisions that are being made and a lot of people are not happy with these political decisions," Furstenau said.

"In an era where we can see the impacts of climate change so vividly, to see governments doubling down on a fossil fuel-driven infrastructure, it makes no sense."

A separate Federal Court of Appeals case on the project, which considers Indigenous issues, is still pending.