The quid pro quo question at the heart of the House investigation received new urgency and a new dimension Monday after explosive testimony by the senior U.S. diplomat in Ukraine.

The U.S. is the world’s top economic and military power. But its stature has been rooted in diplomatic leadership, making its voice matter even where it hasn’t intervened directly. Now, that is changing.

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In many Western democracies, the politics of climate change is opening old fractures that require as much attention as climate change. In France, for example, rural folks dependent on cars for a living rioted last year over a government hike in gas prices, forcing President Emmanuel Macron to retreat and then revamp how he governs. Now it is Canada’s turn to deal with its own rupture over carbon issues.

After an election on Monday, Prime Minister Justin Trudeau faces a possible rebellion in two big energy-rich provinces, Alberta and Saskatchewan, which contain the world’s third-largest proven reserves of oil. Mr. Trudeau’s Liberal Party won the election but lost its majority in the House of Commons. It also lost big in the western Canada. The results mean the Liberals will be forced into alliances with smaller – and greener – parties eager to prevent the export of oil from the two provinces.

Until now, Mr. Trudeau has tried to balance Canada’s interest in being a leader on climate change with its vast oil wealth. In a grand political bargain last year, he was able to impose a national carbon tax while at the same time promising to rescue a proposed project to expand an oil pipeline from Alberta to the Pacific coast.

Now that pipeline may not be built as a result of the election, raising talk in Alberta of splitting the province from Canada. The country’s old east-west divide has been revived, requiring the young prime minister to heal this national breach before it grows. One solution lies in helping Alberta better use its oil revenues to diversify its economy – as Norway has done with its petroleum wealth – lessening the need to extract oil for global markets. Expanding a pipeline may then become unnecessary.

Weaning Canada off fossil fuels will take political patience and a renewed interest in harmony among its provinces. Climate change is urgent, but not as urgent as Canada keeping its unity in order to deal with climate change.