Justin Trudeau is heading back from Davos — and he may soon wish he'd stayed.

As the brand-new prime minister faces a new session of Parliament, he must confront a growing sense that, on one of his signature promises, his time is already up.

It's not about the refugees or the budget. As those promises have proven flexible, Canadians have shrugged. Nobody's calling for Trudeau's head because the Syrian refugees didn't all get here on time.

But Canada's military allies, the Conservative opposition and a restive punditocracy all seem to have lost patience with Trudeau's policy — or the lack of any policy — in Iraq. They have still not heard a coherent explanation of why the Liberals want to pull Canada's six CF-18 fighters out of the war on the so-called Islamic State. Nor have they heard what the government will do instead.

That Trudeau's promise is becoming a serious political liability was evident in the wrenching phone calls he had to make to the families of six Canadians killed in last week's terrorist attack in Burkina Faso. The husband of one victim hung up on him. The wife of another said she was "ashamed" of the plan to withdraw the fighter planes.

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Justin Trudeau told reporters in Davos, Switzerland Friday that Canada would continue to contribute to the anti-ISIS fight militarily - but that Canada's six fighter jets would still be coming home. (Andrew Vaughan/Canadian Press)

Meanwhile, the government stays silent on its rationale — if it has one other than simply to keep a promise, come what may.

The questions keep coming. What's wrong with attacking ISIS from the air? Why has the bombing actually kept pace under the Liberals, while they insist it must end?

"Three months in, the silence grows deafening," wrote Michael Den Tandt in the National Post on Jan. 17. 

"Leaving Canada's CF-18s in place, while claiming they're doing no good and should be pulled out? Claiming a robust ground mission is in the works, while also abjuring any suggestion that Canada will ever be involved in ground fighting? It's incoherent. As long as it remains so, it will weaken Trudeau, while shoring up the arguments of his critics and opponents."

Shut out in Paris

Well, we can't have some ink-stained pundit running our foreign policy. But how about the U.S., France, Britain, Germany, Italy, Australia and the Netherlands?

They, of course, are running the next phase of the war against ISIS. Canada was not invited to the meeting of their defence ministers in Paris. Those nations, according to U.S. Defence Secretary Ashton Carter, "are playing a significant role in both the ground and air components" of the war.

Ouch. Evidently, Canada is not.

This has provoked ominous signs of rebellion in Liberal ranks. Even the apostle of "soft power" himself, former Liberal foreign minister Lloyd Axworthy, complained that the government had failed to say what its new policy will be.

"It's that lack of direction and certainty that I think is causing other people to wonder," Axworthy told Rosemary Barton on CBC News Network's Power & Politics.

"So Australia gets invited — with the same number of aircraft we have still flying — but we don't."

Ouch again.

The Conservatives piled on. Former Tory defence minister Peter Mackay said Canada had been relegated to the "second tier" by its coalition partners. The interim leader, Rona Ambrose, argued that this would never have happened under the Conservatives.

"Six months ago," she said, "we hosted the meeting. Enter Trudeau; we're not even invited to the meeting."

Ambrose says we don't have a clear plan for fight against ISIS0:43

Meanwhile, Trudeau's defence minister made his excuses — "meetings happen all the time," said Harjit Sajjan. Right.

Interestingly, though, Sajjan has made it clear that the loss of Canadian planes will mean a reduction in the "capability" of the coalition — which he does not want to inflict without due deliberation. He happens to be a military veteran. And it happens that, on a daily basis, the planes still fly and the bombs still drop.

But Trudeau still sticks to his pledge. He speaks of Canada's expertise in training, while acknowledging the skill of our pilots. He never says why those pilots must come home.

Pulling out — after Paris?

Under both Conservatives and Liberals, public support has been wide and steady for the bombing mission in Iraq and Syria. That support held strong even at the height of the euphoria that followed Trudeau's sunny swearing-in on Nov. 4. He promptly reaffirmed his promise to end the mission — but, still, an Ipsos poll found 62 per cent in favour of maintaining the bombing, and more than half of those wanted to increase it.

And after the slaughter in Paris, who didn't? It's not hard to see how Trudeau could have pivoted upon that horrifying news to say, "Look, the circumstances have changed and we must stand with the French. ISIS is going global so we're adapting our plan to a changing threat."

Instead, Trudeau dug in. As other nations hastened to increase their contributions, Trudeau talked about sending more trainers. They've done it; he hasn't.

In Davos, all he would say was that "we are committed to withdrawing our six CF-18 fighter jets and looking for another way to continue in the efforts against these global terrorists."

But they're not global enough, it seems, to make us look a little harder, or faster. Meanwhile, the pundits are ramping up their rhetoric.

On CBC's The National, Rex Murphy demanded, "why on earth do we even have fighter jets?" He urged the Liberals to "break this ridiculous, illogical promise" and raged that "Mr. Trudeau hangs on to a pledge no-one wants him to keep and leaves Canada in the international peanut gallery while the adults are dealing with ISIS."

Rex Murphy | Justin Trudeau's Promises3:24

And where, exactly, are the equally passionate counter-editorials? The government ministers insisting that this policy makes sense?

Crickets. But someone will have to come up with some answers, and fast. Trudeau will soon be back, and so will Parliament.