Time heals all wounds, but for the political ties between the prime minister and Alberta's premier, it seems to have only deepened them.
The latest chapter in Justin Trudeau and Rachel Notley's political uncoupling took place Wednesday night, when the premier said her government set up a projection outside a holiday party hosted by the federal Liberals near Parliament Hill in Ottawa.
The projector showed a snippet from an Alberta government ad campaign warning the federal Liberals about the losses incurred by pipeline delays.
"Tonight, the federal Liberals are having their Christmas party in Ottawa," Notley wrote on Twitter.
"While they're celebrating, we didn't want them to forget #WhatCanadaLoses."
Notley, once considered one of Trudeau's close provincial allies, has been upping the pressure on the prime minister as the legal fate of the controversial Trans Mountain pipeline expansion project remains in limbo.
Watch: What's driving Canada's oil prices?
The premier says a lack of new pipelines in her province has led to a glut of supply that has slashed prices to "ridiculously low levels."
Though the federal government bought the pipeline's expansion to try and push it to completion, Canada's Federal Court of Appeal halted the project and ordered the country's National Energy Board to undergo another review of the pipeline's environmental effects and further to consult with First Nations.
Alberta 'essentially giving our oil away' for free: Notley
Earlier this month, Notley ordered a mandatory cut to oil production which amounts to 8.7 per cent of the original output.
"This is creating a huge backlog and forcing the price of our oil to ridiculously low levels.... We are essentially giving our oil away for free," she said.
Since then, the party has been running an advertising campaign in print and on social media to turn up the heat on the government. The ads claim that the lack of a pipeline costs Canadians about $80M a day in lost revenue.
The Alberta government even arranged for the projections to appear on about 20 buildings in Montreal during this month's first ministers meeting.
Notley also took to Twitter Wednesday when Trudeau said his "heart goes out to Albertans" after the province didn't qualify for federal equalization transfer payments.
With files from The Canadian Press