President-elect Trump suggested the idea of merging the United States and Canada after Canadian Prime Minister Justin Trudeau announced his resignation. Trump proposed that there would be no tariffs and increased security if the two countries were one. Trudeau cited the need for a real choice in the upcoming election as the reason for his resignation. Trump expressed that many Canadians would welcome the idea of becoming the United States's "51st State" and highlighted the potential benefits of the merger for the U.S. and its trade deficits. Trudeau's resignation has sparked a competitive race within Canada's Liberal Party to find a replacement, with an emergency meeting scheduled for Wednesday.
Source: https://thehill.com/policy/international/5069487-trump-trudeau-merger-idea/