Justin Trudeau was sworn in as Canada's 23rd prime minister and is facing challenges such as climate change, taxation, the refugee crisis, and the fight against Islamic State militants. Trudeau, leading the Liberal Party to a majority government, has promised to bring 25,000 Syrian refugees to Canada and establish a climate change strategy. He plans to withdraw Canadian combat missions against Islamic State and cancel the purchase of F-35 planes from Lockheed Martin due to cost overruns. Trudeau supports the Keystone XL pipeline with stricter environmental reviews, despite U.S. political opposition. His upcoming global tour includes the G-20 summit, APEC meeting, and Commonwealth summit, followed by the climate talks in Paris. Trudeau's legislative priorities include tax cuts for the middle class, ratifying trade deals, addressing physician-assisted suicide, and amending anti-terrorism legislation. The article also touches on Trudeau's commitment to legalizing marijuana and his approach to earning Canadians' trust through positive politics.