After talking up the prospect of cross-party collaboration in the House of Commons, Liberal and Conservative MPs wasted little time after Parliament resumed Monday before reverting to partisan attacks over housing and the cost of living. The tone was set early Monday afternoon, when the first-ever question period exchange between Prime Minister Mark Carney and Conservative Leader Pierre Poilievre began cordially before turning belligerent. "When I left, there was a Liberal prime minister who was making excuses about breaking promises, running massive deficits. Costs, crime, chaos were all out of control," Poilievre said. "Whereas today... we have a Liberal prime minister breaking promises, making excuses, running massive deficits with costs, crime and chaos out of control." "I understand the leader of the opposition was busy," Carney said in reply — a reference to the Conservative leader losing his seat in the general election before securing another in an Alberta byelection. "He missed the largest tax cut for 22 million Canadians. He missed a cut on the GST for new homes. He missed eliminating all federal barriers to trade." .embed-container { position: relative; padding-bottom: 56.25%; height: 0; overflow: hidden; max-width: 100%; } .embed-container iframe, .embed-container object, .embed-container embed { position: absolute; top: 0; left: 0; width: 100%; height: 100%; } Conservative MPs shouted across the aisle as Carney answered questions. Some joked about the government's new major projects office, saying they've heard it's ready to approve construction of the CN Tower. Hours before question period began on Monday, Government House leader Steven MacKinnon said he was under "no illusions" about the chances for co-operation with Poilievre and his caucus, even though the minority government needs opposition votes to advance its agenda. "Mr. Poilievre has a big decision to make. He can continue with the three-word slogans, or he can sit down and work on real solutions with the Liberal government," MacKinnon said. .embed-container { position: relative; padding-bottom: 56.25%; height: 0; overflow: hidden; max-width: 100%; } .embed-container iframe, .embed-container object, .embed-container embed { position: absolute; top: 0; left: 0; width: 100%; height: 100%; } Addressing the Conservative caucus Sunday, Poilievre said his MPs will work with any party — even as he ripped into the government's track record to date. "(Prime Minister Carney) promised that after 10 years of Liberal government driving up costs and crime and chaos, that he would be different. And yet, sadly, everything is worse," Poilievre said. "That is not what Canadians voted for. What we are getting from Mark Carney is the same Liberal bait-and-switch. Say one thing and do the opposite." MacKinnon briefly outlined the Liberal government's agenda Monday morning. One of the first tasks facing Carney's government is to shore up support for the coming austerity budget, due to be introduced next month, which MacKinnon said will include a "substantial" deficit. MacKinnon acknowledged the minority government will need opposition support to pass other legislation, such as the controversial border security bill, and said it will listen to "constructive criticism" and "responsible alternative policies." The Liberals and Conservatives did work together in the spring to pass the government's major projects legislation. The first projects to be fast-tracked under that legislation were announced last week. There are still wide gaps between the Liberals and Conservatives on other policy areas, including criminal justice. Conservative justice critic Larry Brock said Sunday the Liberals' promised bail reform legislation should "adopt the provisions of the 'jail not bail act' that we Conservatives announced last Thursday." The Conservatives are proposing measures to make it harder for people to receive bail if they have been arrested for or charged with a violent offence in the previous 10 years. MacKinnon said Justice Minister Sean Fraser will introduce bills focused on hate crimes and violence and promised they will be debated with "extreme efficiency." He said the government is open to finding common ground with other parties on policy but won't compromise on "principles." "A wise man once said you don't negotiate on principles, but we can negotiate on details," MacKinnon said. The Liberals hold 169 seats in the 343-seat House of Commons, meaning they only need three additional votes to pass legislation. Bloc Québécois Leader Yves-François Blanchet said Monday he is willing to work with other parties as long as it benefits Quebec. He suggested MacKinnon was sending a mixed message to opposition parties. "Mr. MacKinnon might eventually have to knock on (Bloc Québécois House leader Christine Normandin's) door and explain why he says one thing and it's contrary in the same sentence," Blanchet said. "There will be no negotiation, but we want to collaborate — what does that mean? Obey? Become Liberals? Might not happen." The NDP is in the early days of a leadership contest after winning only seven seats in the April election and losing recognized party status. Quebec NDP MP Alexandre Boulerice said Monday his caucus is ready to collaborate with the government "if it gets results." "Right now, we see a Liberal government with Mr. Carney that is prepared to cut public services when the population is struggling to pay their bills, pay their rent, or pay for their home," he said. "If they don't act accordingly to answer the needs of the population, I don't see how we can support them. But we are open to discussion." Green Party Leader Elizabeth May said she will focus on holding the government's feet to the fire on meeting Canada's international climate targets. Carney and several of his ministers have made vague statements in recent weeks about whether the government intends to back away from its existing greenhouse gas emissions reduction targets, set under the global Paris climate pact. — With files from Sarah Ritchie and Nick Murray. This report by The Canadian Press was first published Sept. 15, 2025.