The hammer blows of last week have left the Trudeau government vulnerable on four fronts.

A win later this month at the North American free-trade talks would go a long way to repairing the damage. But if those talks fail, the Liberals will be challenged to win the next election, a prospect that seemed unlikely mere months ago.

On the NAFTA front, U.S. President Donald Trump continues to tweet antagonisms, declaring over the weekend that “there is no political necessity to keep Canada in the new NAFTA deal;” that “decades of abuse” by our country toward the Americans must end; that if Congress does not bend to his will he will cancel NAFTA entirely; and that “we shouldn’t have to buy our friends with bad Trade Deals and Free Military Protection!”

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Canadian – and American – negotiators will ignore all this. We have a remarkable situation in Washington in which the President is estranged from his own administration. For example: Senior officials crafted an agreement with other NATO countries in advance of last July’s summit, presenting the accord as a fait accompli to the President, who had no choice but to sign.

In this case, negotiators will try to tune out the President’s tweets and focus on crafting a deal both sides can live with. Progress was made last week, according to a government official who spoke Sunday on background, and agreement remains possible.

With good will on both sides, the U.S., Canadian and Mexican delegates should be able to reach an accord that the American team can present to the President. Facing a Congress already rebelling at the idea of a NAFTA without Canada, Mr. Trump may have no choice but to sign.

But if those talks fail and Canada finds itself outside the agreement, dependent on Congress to veto a Mexico-U.S. deal and facing crippling automotive tariffs from a vengeful President, then God help us all.

On the second front, how politically damaging was the decision by the Federal Court of Appeal that halted construction of the Trans Mountain pipeline, pending further environmental review and Indigenous consultation? Imagine this attack ad:

First a clip of Justin Trudeau declaring “This pipeline will get built.” Finance Minister Bill Morneau: “This pipeline will get built.” Natural Resources Minister Jim Carr: “This pipeline will get built.” An accelerating montage of identical quotes from these three: in the House, in TV interviews, in speeches, over and over and over again. Then a photo of an abandoned Trans Mountain work site. Headlines appear on the screen: “Thousands of Trans Mountain workers laid off.” “Pipeline delayed for another year.” “Billions of taxpayer dollars wasted.”

What more is there to say? Only this: The court seemed to believe that the necessary agreements could be quickly reached. If that turns out to be true, work could resume before the next election. Otherwise, cue the commercial.

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On the third front, the carbon tax was supposed to be this government’s answer to the crisis of global warming. But NDP Premier Rachel Notley has pulled Alberta out of the federal-provincial program in retaliation for Ottawa’s failure to get Trans Mountain approved. Saskatchewan and Ontario are already out. Count on Ontario Progressive Conservative Premier Doug Ford to campaign heavily during the federal election in an effort to defeat the Liberals.

Because the carbon tax is an issue on which Conservatives and Liberals invariably disagree, this front could get particularly bloody.

Finally, there is the issue of refugee claimants crossing the border from the United States. How many will there be next year? If there are fewer, this issue goes away. If there are more, it could become a conflagration, bringing the same nativist, anti-immigrant tensions to Canada that bedevil the United States and Europe.

That’s a lot for one party to have on its plate 13 months before a federal election.

It remains to be seen whether Conservative Leader Andrew Scheer can convince voters he is a safer bet than Mr. Trudeau, or whether NDP Leader Jagmeet Singh can win the upcoming by-election, take his seat in the House, and revive his party’s flagging fortunes.

But at this point in time, who would have thought the Liberals could be in so much trouble?