Tensions with N.S. premier simmered as Poilievre made his sole stop in the province

While Houston had previously said he would stay out of the federal campaign, sources say there has been tension between the two leaders for months. 

During last year's provincial election, Houston told reporters he would not be inviting Poilievre to campaign with him, saying he's not a member of any federal party.

"There is no federal equivalent," said Houston last November. "I'm the leader of the Nova Scotia Progressive Conservatives. There is a Conservative Party of Canada. It's a completely different party with its own leader."

Frosty call with campaign manager

Four provincial sources, who CBC News is not naming because they weren't authorized to discuss internal party matters, told CBC News that soon after, Houston's staff received a phone call from Conservative national campaign director Jenni Byrne.

The sources claim Byrne told Houston's team that if Poilievre went on to become prime minister, they would not lift a finger to help the provincial party.

The call changed the relationship between the two camps, according to sources.

On the eve of Poilievre's visit, Houston released a campaign-style video on social media, prompting some to wonder whether he was eyeing Poilievre's job.

The video included a speech Houston gave during the winter session of the Nova Scotia legislature. Houston and opposition leaders all delivered speeches in the face of threats of tariffs from the United States government. 

The premier's was in the vein of the "I Am Canadian" beer ad. Houston concludes his speech by saying "I am Nova Scotian."

Speaking to reporters on Thursday, Ontario Premier Doug Ford — a friend and ally of Houston — said he had been "busting [Houston's] chops" over the video. 

The video included clips of the two Progressive Conservative premiers together. 

"I told him I love it," said Ford, declining to elaborate on what else he said to the Nova Scotia premier.   

In a statement, the Conservative Party of Canada did not deny that the phone call with Byrne took place, but said that the two leaders have "communicated about issues of importance to Nova Scotians, both before and after the recent provincial election."

The statement said, if he is elected, Poilievre "looks forward to working closely with Premier Houston."

A statement provided by Houston's communications director, Stephen Moore, said Houston's "main concern is Nova Scotia" and he "will work with whomever forms the next government."

Earlier this year, Houston wrote identical letters to both Liberal Leader Mark Carney and Poilievre outlining what he hoped the next federal government would prioritize for Nova Scotia. 

Poilievre's relationship with premiers has been under the microscope during the federal campaign, after Ford declined to endorse the Conservative leader but had breakfast with Prime Minister Mark Carney during the brief pre-campaign window after Carney was sworn in.

Ford defended his former campaign manager's criticisms of Poilievre's campaign, telling reporters "sometimes the truth hurts."

He had said he would stay out of the campaign to focus on his province.

Poilievre has been endorsed by Alberta Premier Danielle Smith and Saskatchewan Premier Scott Moe.