Just a few months ago, the U.S. government wasn’t participating in a global treaty to reduce harmful gas emissions, and legal challenges were threatening to kill a carbon tax imposed by the Canadian government as the centerpiece of its effort to reach net-zero emissions by 2050. Now, everything is different: Joe Biden is in the White House promising to restore America’s global leadership on climate, and the Supreme Court of Canada has blessed the carbon tax championed by Prime Minister Justin Trudeau.

To Canada’s environment minister, Jonathan Wilkinson, the path is now clear for North America to take big steps to mitigate climate change. Biden and Trudeau both plan to present new, more aggressive emissions targets at the U.S. Earth Day Summit starting April 22.

“The calls are far more aligned,” Wilkinson said in an interview, describing interactions between the two governments. “I don’t want to speak ill of the Trump administration, but certainly there is a common perspective as we look forward.”

Differences over how to lower Canada’s emissions have created discord between the ruling Liberals and regional governments, especially in energy-rich Western provinces. Ontario, Alberta and Saskatchewan filed the lawsuit against Trudeau’s carbon tax.

It’s unclear what the holdout provinces will do now that their legal challenge is dead. On the day of the Supreme Court ruling, Alberta Premier Jason Kenney chastised “Ottawa elites” and said they didn’t respect Western Canada. “We will continue to fight for our provincial power,” he said, without explaining further.