The Supreme Court of Canada has ruled in favour of Yukon First Nations in their fight to protect the Peel watershed region, overturning a decision that rolled back years of planning and ordering the government to consider a final recommended plan proposed by an independent commission.

The unanimous ruling released Friday ends a five-year legal battle between the Yukon government and a group of First Nations and environmental groups. The case was fought in territorial courts before the First Nations and environmental groups appealed to the country's highest court.

A Supreme Court hearing was held in Ottawa in March.

In the ruling Friday, written by Justice Andromache Karakatsanis, the court upheld a ruling by a trial judge to quash the territorial government's final land use plan, ordering the planning process to resume at an earlier stage.

Changes made by the territorial government's land use plan "did not respect the Chapter 11 process," the decision reads. "Respect for this process is especially important where, as here, the planning area includes First Nations' traditional territories within non-settlement areas.

"As both the trial judge and Court of Appeal noted, Yukon's conduct was not becoming of the honour of the Crown."

Gordon Christie, a University of British Columbia law professor who has studied the case, said Friday's decision affirms the authority of Yukon's land claim agreements — and sends a signal to governments elsewhere.

"It's a win for the First Nations and groups that made this challenge, but it's really a win for the treaty, which is an agreement between Canada and the First Nations — so it's really a win for reconciliation," he said.

"That's what won today, was that agreement."

The dispute centres on a land use plan for the Peel region, a 68,000-square-kilometre swath of pristine sub-Arctic wilderness that represents about 16 per cent of Yukon. (CBC)

Competing plans

The dispute has centred on Yukon's land use planning process for the Peel watershed and what happens when a government fails in its treaty obligations.

The Peel watershed is a roughly 68,000-square-kilometre swath of pristine sub-Arctic wilderness that represents about 16 per cent of Yukon. It's larger than Nova Scotia.

In 2011, after years of work, an independent commission came up with a final recommended land use plan for the Peel region. It would have protected about 80 per cent of the region from development.

The Yukon government didn't like that idea, and in 2012 it presented its own plan, which would have protected just 30 per cent of the region.

Peel watershed region is a 68,000-square-kilometre swath of sub-Arctic wilderness that represents about 16 per cent of Yukon 0:21

Local First Nations and environmental groups cried foul, and took the government to court. They argued the territorial government had breached its treaty obligations under Yukon's Umbrella Final Agreement (UFA), which was signed by First Nations and the territorial government in 1990. It describes a collaborative process for land use planning.

The lower courts agreed that the Yukon government derailed that process by ignoring the commission's recommended plan in favour of its own.

The Supreme Court agreed with that assessment Friday, returning the process to when the commission's final recommended plan was first presented to the government — an option favoured by First Nations and environmental groups. The government sought to return the process to where input from all stakeholders is considered, essentially restarting land use planning for the watershed.

The ruling said the government modified the commission's final plan for the watershed so significantly "as to effectively reject it."

"Imagined as a conversation, Yukon chose not to propose a point for discussion, but then proceeded to advance its point in the most general terms and only after the discussion had substantially progressed."

'Nobody expected that'

David Loeks, who chaired the Peel planning commission, said Friday the government's introduction of its own plan in 2012 was a real curveball.

'To get here, and get this level of clarity, is very welcome,' said Dave Loeks, who chaired the Peel watershed planning commission.

"When that played out, my jaw and many other people's jaws collectively dropped — nobody expected that. So to get here, and get this level of clarity, is very welcome."

Jeff Langlois, who represented the Gwitch'in Tribal Council as an intervener in the case, agrees that the top court's opinion is clear — the Yukon government should not have ignored a process that's spelled out in land-claims agreements.

"You have to respect the terms of these agreements, and the court will step in and quash actions that don't comply with those," Langlois said.

"That's what the court said here — they said that's the obligation of the parties, to participate in these collaborative processes diligently. It won't do to wait till the end of the day and just assert what you would have otherwise said, as if the treaty had never been signed," he said.

Restarting the process

Friday's decision has been highly anticipated in Yukon, where the dispute became a flashpoint for government-First Nations relations in recent years.

Representatives of several Yukon First Nations and environmental groups were in Ottawa last March for the Supreme Court hearing. They've planned a news conference for Friday afternoon to discuss the court's decision. (Cheryl Kawaja/CBC)

Yukon government lawyers argued the Peel planning process should go back to where input from all stakeholders is considered. But the First Nations and environmental groups wanted the commission's final recommended plan from 2011 to stand, allowing the government only minor modifications.

Friday's decision takes the government's 2012 plan off the table, but also leaves the door open for it to ultimately reject the commission's final plan.

"It is premature to interpret the scope of Yukon's authority to reject the Final Recommended Plan after it consults with the affected First Nations, and it is unnecessary to do so in order to resolve this appeal," the decision reads.

The court orders the process back to the point where "Yukon can approve, reject, or modify the Final Recommended Plan as it applies to non-settlement land after consultation with the specified parties."

'I'm hopeful that governments of Canada are slowly waking up to their responsibilities under the agreements,' said Gordon Christie, a law professor at the University of British Columbia. (UBC)

Christie says that allows for the possibility of more legal battles down the road.

"There's certainly room for things to unfold here in an unfortunate direction," he said.

"I don't think it will. I'm hopeful that governments of Canada are slowly waking up to their responsibilities under the agreements," he said.

In fact, Yukon's Liberal government — elected last year, when the Yukon Party was handily ousted — has signalled that it would accept the commission's final recommended plan.

Premier Sandy Silver was expected to make a statement at noon PT on Friday, to respond to the court's decision.

Representatives from the Tr'ondëk Hwëch'in, Na-Cho Nyäk Dün, and Vuntut Gwitchin First Nations, as well as the Canadian Parks and Wilderness Society and the Yukon Conservation Society, have also planned a news conference on Parliament Hill on Friday afternoon to discuss the decision.

The event will be live streamed at the Kwanlin Dün Cultural Centre in Whitehorse, beginning at 10 a.m. PT.