Canada's Finance Minister Chrystia Freeland quit on Monday after clashing with Prime Minister Justin Trudeau on issues including how to handle possible U.S. tariffs, dealing another blow to an already unpopular government.In a stinging resignation letter, Freeland dismissed Trudeau's push for increased spending as a political gimmick that could hurt Ottawa's ability to deal with the 25% import tariffs U.S. President-elect Donald Trump says he will impose.Freeland said she was quitting in the wake of a meeting last Friday with Trudeau, who asked her to take on a lesser post after the two had argued for weeks over spending.Her resignation came just hours before she was due to present a fall economic update to parliament, a document widely expected to show the minority Liberal government had run up a much larger 2023/24 budget deficit than predicted. Officials said the document would be unveiled on Monday as planned.The resignation by Freeland, 56, who also served as deputy prime minister, leaves Trudeau without a key ally when his government is already in trouble."This will likely trigger a leadership crisis within the Liberal caucus ... (it) is politically and personally devastating for Trudeau," said Nik Nanos, founder of the Nanos Research polling firm.Polls show the ruling Liberals, who have been in power since November 2015, are set to be crushed in an election that must be held by late October 2025.Freeland, a former journalist, served as trade minister and then foreign minister before taking over the finance portfolio in August 2020. As minister, she oversaw the massive government spending campaign to deal with the damage done by COVID.A smiling Trudeau did not answer reporters' questions as he walked into a regularly scheduled cabinet meeting. Colleagues were clearly stunned."This news has hit me really hard and I'll reserve further comment until I have time to process it," said an emotional Anita Anand, president of the Treasury Board.Trudeau has been under pressure for months from Liberal legislators alarmed by the party's poor polling numbers. But he is safe for now, since Canadian political leaders are chosen by special conventions.