How much is the carbon tax climb-down worth to Justin Trudeau’s government?

Open this photo in gallery:

The human backdrop at a political event means taking real people and reducing them to scenery, curated and arranged like a person bouquet.

If you’re a supporter who gets plucked out of the crowd to stand onstage, it must feel like going out to run errands and ending up as an extra in a movie. If you’re a politician, it has to be less fun. You have skills and accomplishments, and presumably you take pride in something beyond your ability to applaud like a trained seal.

But at Prime Minister Justin Trudeau’s recent press conference announcing that his government was suspending the carbon tax on home heating oil, the human backdrop was a special fascination.

“All of you worked incredibly hard to make sure we got to this place,” Mr. Trudeau said of the 15 or so Liberal MPs from Atlantic Canada behind him. (The East Coast is where a critical mass of homes use expensive and price-volatile heating oil.)

The Prime Minister worked valiantly to present this as a careful, high-minded plan to reduce emissions faster, with the happy side-effect of tackling affordability.

If you’ve never seen someone’s soul vacate their body in the middle of a press conference, watch Mr. Trudeau as he says, “We are doubling down on our fight against climate change and keeping true to the principles that we are supporting Canadians while we fight climate change.”

There is a very different, nearly universal understanding of what’s really going on here: That the “incredibly hard” work of Atlantic MPs consisted of pointing at polls that have had them in free-fall since federal carbon pricing kicked in this summer, possibly while clutching sharp sticks.

So behind Mr. Trudeau was a human backdrop that was anything but wallpaper. They weren’t the set decoration; they were the reason for the show.

When a reporter asked whether this was about not wanting to lose seats (24 of the 158-member Liberal caucus are East Coasters), several reacted with delicate shock. Lena Diab of Halifax West shook her head and looked off to one side, as though she could not bear to gaze directly upon a notion so crass.

A few blocks away, Senator Paula Simons was in the Senate with her colleagues, when Leo Housakos, a vocal opponent of the carbon tax, rose to announce that Mr. Trudeau was “putting a pause on the carbon tax for home heating.” He didn’t have the details quite right, but Ms. Simons, a journalist by trade, immediately searched online. “Really?” she remembers thinking. “Now?!”

An independent senator from Alberta, she had just finished agonizing over her own votes on C-234, which would remove the carbon tax on natural gas and propane used for drying grain and heating farm buildings.

On one hand, it was obvious that farmers were being affected by carbon prices as few other small businesses were, she said in a speech a few days later. “But I am also a believer in carbon taxes,” she added. “They are a transparent, straightforward way of incentivizing people to reduce fossil fuel use.”

As the bill worked its way through the agriculture committee, Ms. Simons listened, asked questions and thought hard.

Eventually, she concluded that the exemption for grain drying made sense because there were no real substitutes on the market. So, with no small amount of difficulty, she voted for an amendment that would limit the exemption to that and scrap the carve-out for heating farm buildings.

“I heard from many who were upset with my decision,” she said in her speech. “Either because they felt I had betrayed farmers or because they felt I had betrayed my principles and the planet by voting in any way for a bill that rolled back taxes and could be a Trojan horse – a wedge in the door to end carbon taxes for good.”

Still, she felt like she’d done the right thing, and she met with several farm lobby groups in the days that followed to explain herself.

And then Mr. Trudeau stepped out in front of those Atlantic MPs.

“I took a principled stand in defence of the carbon tax regime, and have now sort of had the floor open beneath my feet,” Ms. Simons said in an interview this week. “It makes it very difficult for me to go back and say to Alberta farmers, I voted against this to protect the principle of carbon taxes without bespoke exemptions. And now there’s a bespoke exemption for particular regions.”

Ms. Simons is not throwing herself a pity party; I asked for her views because I thought she had an illuminating vantage point. And as she points out, she is amply compensated for a job where being popular is not the point, because making unpopular decisions is.

“As an Albertan and a strong believer in a united Canada, I fight all the time in Alberta to convince people that Albertans need to step up and be leaders in Confederation, instead of always threatening to take our ball and go home,” she says. “At a time when separatist sentiments in Alberta are on the upswing, it is uniquely unhelpful to create a new carbon tax regime that looks as though it is designed to be prejudicial to people on the Prairies.”

This is precisely what’s so bewildering and galling. This climb-down undermines so many big things: A signature policy that was supposed to represent what this government wanted to be in the world; the political and practical justification for it; the political and financial capital already spent; unity and cohesion right when different slices of the country are primed to see unfairness everywhere. It’s hard to imagine what Mr. Trudeau and his government could possibly have pictured on the other side of the scales to make this worthwhile.

A happy, politically waterproofed human backdrop only weighs so much.