U.S. President Donald Trump’s trade war and annexation threats have upended Canada’s election and dramatically improved the fortunes of the Liberal Party, which could win a fourth consecutive term in power next week.

Canada is heading into federal elections, where Prime Minister Mark Carney is vying for a chance to continue leading the country, as tensions over trade grow with the US.

There is no fixed term for the Prime Minister in Canada. He or she can hold the office as long as they have the confidence of the majority of the House of Commons. The shortest tenure in Canadian political history was that of Charles Tupper.