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Prime Minister Mark Carney speaks at the Forever Canadian rally at the BMO Centre in Calgary, on Thursday.Todd Korol/Reuters

Prime Minister Mark Carney has taken his unity message to Alberta ahead of Monday’s referendum, urging people to vote for the province to remain in Canada and reject Premier Danielle Smith’s other nine ballot proposals.

In prepared remarks ahead of a speech in Calgary on Thursday evening, Mr. Carney spoke of the country’s strength when united and warned Albertans of the consequences of voting against choosing to keep the province wedded to Confederation.

“At this pivotal moment, Albertans have a choice: to build a stronger Alberta and a greater Canada to leave for our children, or to burden them with years of deep division and great uncertainty,” Mr. Carney was set to tell a packed house at a downtown Calgary rally.

Monday’s referendum will ask voters to weigh in on 10 questions, one of them on whether Alberta should remain in Canada or hold a second, binding vote on separating. The other nine questions, authored by Ms. Smith’s government, deal with limiting some non-permanent residents’ access to social services, charging them fees for health care and education, and numerous constitutional changes such as abolishing the federal Senate.

The Prime Minister has been critical of Ms. Smith’s decision to call the referendum. In May, he described it as a “dangerous bluff,” likening it to Britain’s 2016 vote to leave the European Union. (Mr. Carney was governor of the Bank of England at the time.)

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He used similar language for his speech on Thursday night: “This is not poker. A vote against Canada is a dangerous bluff that will lead to years of deep uncertainty and lost opportunities,” he said in his prepared remarks.

“Our country and your futures are too precious to play games with.”

Mr. Carney has spent much of the referendum campaign on the sidelines, choosing to make his pitch to Albertans indirectly, by demonstrating Ottawa’s willingness to co-operate with the province. This has included dramatic policy shifts, particularly around environmental safeguards, and standing with the Premier as they announced a proposed oil pipeline to the West Coast.

Alberta’s referendum – the first time the province has put a secession question to voters – is occurring at a time of tremendous stress on national unity. While many Albertans prepare to vote on Monday, a newly elected separatist Quebec government will pose challenges for Ottawa, and U.S. President Donald Trump has shown few signs that the continuing tariff war and musings about annexation will end.

On Thursday night, Mr. Carney was set to say that the referendum “comes at the worst possible time,” pointing to what he described as a more dangerous and divided world.

“Some outside our borders are working to break us so they can own us.”

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Mr. Carney’s push alongside Ms. Smith to build a new bitumen pipeline – most recently by designating it a project of national interest – has underscored a desire to blunt many Albertans’ deep frustration with Ottawa’s direction on energy and environmental policy under his predecessor, Justin Trudeau.

“I won’t sugarcoat it: some of those threads have needed to be repaired. The frustrations that many Albertans have felt are real,” Mr. Carney was expected to say at the Thursday event, held by Forever Canadian, one of the most prominent federalist groups in the province.

He added that recently, Albertans were made to feel their “energy contributions were running against the tides of history.”

“What should have brought us together began to divide us. Contributing to a half century of politics that have too often pulled us apart,” he said in his prepared remarks.

It was the second time this week that the Prime Minister had made the case for unity directly to Albertans. On Monday, he released a short video shot in a classroom at St. Francis Xavier Catholic High School in Edmonton, which he attended as a teenager. In the video, he said that Albertans were being asked to decide on what he called “a long and uncertain process” of separation. “We are stronger together,” he said.

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But Thursday was the first time he had encouraged Albertans to vote against the Premier’s nine proposals on immigration and constitutional changes.

As he made several stops in Calgary earlier in the day, he told Albertans to vote “no to the nine,” putting him in direct opposition to Ms. Smith, whose government has spent $4-million in advertising to campaign in favour of the proposals.

The Premier says she needs approval on them to fortify her mandate, and that they would provide leverage to gain more autonomy within Confederation.

Ms. Smith clapped back at Mr. Carney’s comments later in the day, writing on social media that “it appears that he has yet to fully understand just how damaging the open-border policies of his predecessor were.”

The Prime Minister is continuing his pro-Canada campaign on Friday in Red Deer, Alta., where he’ll share a stage with Ms. Smith, and attend another Forever Canadian rally in Edmonton in the evening.

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Conservative Leader Pierre Poilievre is scheduled to give an address on Friday morning in Calgary at the Canada Strong and Free Network conference, a conservative gathering.

Advance voting opened earlier this week. Elections Alberta said in an e-mail on Thursday morning that roughly 815,000 Albertans had so far cast their ballots – about 27 per cent of all eligible voters.

Campaigners have been divided on how Mr. Carney should support the federalist effort and whether Ottawa should bankroll groups fighting to keep Alberta in Canada. (Alberta’s election-finance rules prohibit the federal government from funding referendum advertisers.)

Some have argued that the Prime Minister shouldn’t leave any cards on the table and use his immense popularity in Alberta to his advantage by giving the federalist side a boost. Others have said he should keep his hands out of it, and that circumventing election-finance rules would backfire.

Mr. Carney in September said his government wouldn’t help fund Alberta’s numerous pro-Canada campaigns, which struggled to raise money through the summer.

Federalist groups have since closed the distance on separatist campaigns that were flush with cash early on. Separatist groups have now scooped up about 59 per cent of all donations during the campaign, down from early September when roughly 75 per cent of all contributions were floating to them.

With a report from The Canadian Press