Open this photo in gallery New Ontario Premier Doug Ford, centre, tried but failed Thursday to persuade other premiers such as Philippe Couillard of Quebec, left, and Brian Pallister of Manitoba, to join his fight against the carbon tax. Andrew Vaughan/The Canadian Press

Doug Ford and Scott Moe are coming up empty at a premiers' conference as they scope for allies in their legal fight with Ottawa over the federal government’s plan to impose carbon pricing on provinces that don’t already have it.

Ontario’s new Progressive Conservative Premier set the agenda early Thursday by announcing that his government will intervene in favour of Saskatchewan’s court case against the federal climate plan.

“I’m here to gather support among my provincial counterparts against the federal carbon tax,” Mr. Ford announced alongside Mr. Moe, Saskatchewan’s Premier.

Story continues below advertisement

But as the day went on, other premiers said they had no interest in joining that fight.

“What we’re told is that the provinces’ case will not stand up. That is the advice that we have been hearing,” said New Brunswick Premier Brian Gallant, who is hosting the Council of the Federation conference at a southern New Brunswick resort.

Related: Ontario Premier Doug Ford courts allies in carbon fight with Ottawa

Globe editorial: Doug Ford’s carbon tax folly

Explainer: Doug Ford Year One: What’s happened so far in the new Ontario

The federal government has passed legislation that would allow it impose a carbon tax in provinces and territories that fail to create a carbon-pricing regime of their own that meets minimum standards. Ottawa has said any revenue collected by a federal carbon tax would be returned to the province in which it was collected, either directly to the government or to individual citizens of that province.

Manitoba’s Brian Pallister, a Progressive Conservative Premier, has also indicated that he does not expect Saskatchewan to win in court and will not join the legal challenge.

Story continues below advertisement

A spokeswoman for Prince Edward Island Liberal Premier Wade MacLauchlan ruled out an alliance with Ontario and Saskatchewan. “We would rather focus our energy addressing climate change, not a court challenge,” Mary Moszynski said on Thursday.

B.C.'s NDP Premier John Horgan wouldn’t rule out support for Saskatchewan’s legal challenge to Ottawa’s constitutional powers over environmental policy, but only because B.C. is already fighting in court to block Ottawa’s plan to force a pipeline expansion through his province. Mr. Horgan said he supports carbon taxes and B.C.'s experience shows they are good for the environment and the economy.

In addition to climate change, removing internal trade barriers between provinces emerged as a top-of-mind concern among premiers.

Moments after premiers called for a first ministers’ meeting this fall with Prime Minister Justin Trudeau focused on expanding international and internal trade, Mr. Trudeau’s office announced that such a meeting will take place. Premiers also said they would be working into the evening Thursday in the hope of being able to announce specific measures on internal trade by the time the summit concludes Friday.

Manitoba is urging premiers to promise concrete action by year-end to harmonize regulations related to abattoirs, business registration, first-aid requirements and trucking industry rules, as well as progress on reducing barriers related to alcohol.

Mr. Ford’s arrival on the national scene clearly raises questions about whether Ottawa can succeed in establishing its carbon plan. British Columbia, Alberta, Manitoba and Quebec have already adopted or announced carbon-pricing plans that they expect will meet the federal threshold.

Story continues below advertisement

The four Atlantic provinces − all currently led by Liberal governments − are promising to release plans this year that they say will exempt them from the federal carbon tax.

The political dynamic could change further, as some governments that currently support the federal plan will soon face off in elections against opposition leaders – such as United Conservative Party Leader Jason Kenney in Alberta – who have said they would fight Ottawa on this matter.

In April, the Saskatchewan Party government announced that it would be asking the Saskatchewan Court of Appeal to rule on whether Ottawa has the constitutional authority to impose such a tax.

“A one-size-fits-all carbon tax fails to recognize the diverse nature of our great Canadian economy,” Mr. Moe said Thursday. Saskatchewan’s climate plan includes industrial regulations to reduce emissions and a focus on new technology, such as carbon capture and storage.

All provinces and territories have until Sept. 1 to submit their climate plans to Ottawa for a determination of whether the plans are sufficient to avoid the imposition of the federal carbon tax.

The federal carbon tax would start at $20 a tonne of carbon emissions in 2019, rising to $50 a tonne by 2022.​

Story continues below advertisement

Federal Environment Minister Catherine McKenna said Ottawa is confident that it has the right to impose a carbon tax in provinces that don’t have their own system, and criticized Mr. Ford for failing to offer any plan to deal with greenhouse-gas emissions.

“It is really disappointing that the Ford government is going to spend $30-million of taxpayers’ money fighting climate action,” Ms. McKenna said in an interview while touring Southern Ontario.

Nova Scotia Premier Stephen McNeil will be unveiling details of the province’s planned cap-and-trade system in the next few weeks, and the province is confident it will satisfy the federal government’s standards, an official said Thursday.

New Brunswick’s plan involves the redistribution of existing gas taxes toward climate-change measures, which has generated concern from Ms. McKenna because it does not clearly impose a price on emissions that is higher than what is already in place.

Mr. Gallant said New Brunswick will ensure that it has a provincial plan that meets the federal criteria, even if it means making adjustments in response to federal concerns or borrowing ideas from other provinces. He said if Saskatchewan does win its legal fight with Ottawa, New Brunswick and other provinces may have to reconsider their own climate plans.

“With all due respect to Minister McKenna, I think she has other provinces that she has a lot more trouble convincing to put a plan in place,” Mr. Gallant said Thursday. “So I would respectfully suggest to her that she focus on them.”