Stephen Harper says Pierre Poilievre has the best chance to win the next federal election

Former prime minister Stephen Harper says Pierre Poilievre is the Conservative leadership candidate with the best shot at leading the party to victory in the next federal election.

Harper's declaration came in a Monday evening video posted to Facebook and Twitter, in which he described Poilievre's ability to galvanize support from new members as a critical ingredient for success.

"That's how we win the next federal election, and in my opinion, Pierre has made by far the strongest case," Harper said.

Poilievre's campaign claims to have signed up more than 300,000 members to vote in the leadership race.

Harper also praised Poilievre, a longtime MP serving the Ottawa-area riding of Carleton,as a powerful communicator who has identified the most pressing issues facing Canada.

"He's been talking about the issues, especially the economic issues, that matter," Harper said, listing Canada's debt, inflation and housing troubles among the problems Poilievre is prepared to address.

Harper also said Poilievre recognizes "the need to fix the institutions that are failing Canadian families."

A central theme of Poilievre's leadership campaign is a promise to wipe out "gatekeepers" that he says are standing in the way of economic growth and sensible governance.

Poilievre also said during a leadership debate in May that he would fire Bank of Canada governor Tiff Macklem. He's blamed the central bank and Liberal government for overseeing what he says is reckless monetary policy that has pushed inflation to levels not seen in decades.

Poilievre served in two cabinet roles under Harper, first as the minister of state for democratic reform from 2013 to 2015, followed byminister of employment and social development, until the Conservatives lost the federal election later in 2015.

Harper's comments markthe first time the former prime minister has weighed in during a leadership race for the party he helped to form. He did not make any similar public declarations of support in the 2017 or 2020 leadership contests.

Other candidates in the Conservative leadership race are Jean Charest,Leslyn Lewis, Roman Baber and Scott Aitchison.

Theparty will announce its new leader on Sept. 10.