You can't have it all.

It's a lesson most Canadians learn as soon as they're old enough to plunge a fist into a birthday cake.

So why do politicians continue to promise us the world? Environment and economy. Indigenous reconciliation and mega-projects.

The Federal Court of Appeal delivered more than just a potential death blow to the Trans Mountain expansion Thursday.

The judges also dealt a stunning rebuke to governments sidestepping real — and intractable — issues for threatened species and First Nations with platitudes instead of substantive answers.

'The courts will hold them to account'

This isn't an argument for or against the pipeline.

Even the Explorers and Producers Association of Canada — which represents oil and gas entrepreneurs — lamented the major resource project approval process as "close to collapse under the weight of too many conflicting interests."

The federal court of appeal's decision means the future of the Trans Mountain pipeline expansion is on hold while the government grapples with legal issues. (Chris Helgren/Reuters)

Yet Prime Minister Justin Trudeau once again vowed the expansion will proceed.

The legal questions will be settled. The pipeline paid for. And the whales and First Nations happy.

But how?

"Politicians who think they can take shortcuts and paper over differences and ignore factors that they're bound to consider — the courts will hold them to account for that," says University of Victoria law professor, Chris Tollefson, who heads the Pacific Centre for Environmental Law and Litigation.

'Generic and vague' responses

The court of appeal decision faults the pipeline approval process on two fronts: consideration of the project's impact on the iconic southern resident killer whales; and the duty to consult with affected First Nations.

The first point is a little tricky to unravel: the National Energy Board concluded increased shipping traffic would result in "significant adverse effects" to the endangered orcas.

The National Energy Board concluded that increased shipping traffic would result in "significant adverse effects" to the southern resident killer whales. (Elaine Thompson/Associated Press)

But the board then defined the scope of the project so as not to include those very impacts.

"The unjustified exclusion ... resulted in successive deficiencies," the ruling says.

"The resulting flawed conclusion about the effects of the project were 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 legislation requires."

The reasons for the court's criticism of consultation with First Nations are more straightforward. They're also familiar to anyone who's ever argued with a wall of government bureaucracy.

The judges note the "generic and vague" responses the Tsleil-Waututh and Squamish First Nations got to extensively documented fears about marine shipping and oil spills.

"A review of the record of the consultation process discloses that Canada displayed a closed-mindedness," the decision says.

"Canada was obliged to do more than passively hear and receive the real concerns of the Indigenous applicants."

'It can't be a paper shuffle'

Essentially, the ruling contrasts rhetoric with action.

"It can't be a paper shuffle. It can't take the form of lip service," says Tollefson.

"Government can't go into that process with its mind closed, with its mind made up. It has to honourably negotiate with those nations. And if it fails to do so, it will have to live with the consequences, as it is now."

Trudeau has challenged critics. He says responsible government has to promote the country's economic interests and protect the environment at the same time.

Tsleil-Waututh's Rueben George welcomed the federal court of appeal decision which he says validates First Nations concerns about government consultation. (Darryl Dyck/Canadian Press)

That's left people on both sides of the debate calling him a hypocrite: opponents say he's sacrificing the climate for the sake of business, and proponents say a country can't run on whales and good wishes alone.

To be fair, it's not the only tightrope Trudeau has to walk. Alberta and B.C. are at war over the project.

And while the court decision was a victory for some First Nations, the project's death would mark a serious loss for the dozens who signed on to the expansion.

'It's in everybody's backyard'

The ruling comes at an interesting time: the end of a summer which saw forest fire smoke cloud skies and clog lungs on both sides of the Rockies.

Rueben George, manager of the Tsleil-Waututh's Sacred Trust initiative, says politicians should contemplate that reality before making any promises about what happens next.

"People are waking up to the pollution. People are waking up to the droughts. People are waking up to the fires," he says.

"And it's in their backyard now. It's not just here or there. It's everywhere. And when those things happen, things need to be done and action needs to be taken."

You can't have it all.

Sometimes governments have to choose between 'natural' resources: the treasures below ground or the creatures and cultures above.