U.S. President-elect Donald Trump used Prime Minister Justin Trudeau’s decision to suspend democracy by proroguing Parliament to float the idea of merging Canada with the U.S. – an idea he has increasingly referred to when discussing relations between the two countries.

In a surprise turn of events, Canadian Prime Minister Justin Trudeau announced his resignation as leader of the Liberal Party and as Prime Minister on Monday, set to take effect once a new leader is chosen.

Trump, who has pledged to impose 20% tariffs on Canada until it resolves its border crisis, suggested that Canada should consider merging with the United States, becoming its 51st state.

“Many people in Canada LOVE being the 51st State. The United States can no longer suffer the massive Trade Deficits and Subsidies that Canada needs to stay afloat. Justin Trudeau knew this, and resigned,” Trump posted on Truth Social.

“If Canada merged with the U.S., there would be no Tariffs, taxes would go way down, and they would be TOTALLY SECURE from the threat of the Russian and Chinese Ships that are constantly surrounding them. Together, what a great Nation it would be!!!”

It’s not the first time that Trump has referred to the idea of Canada becoming the “51st state.” He has in past comments called Trudeau Canada’s “governor” and even jokingly brought up the idea at a Mar-a-Lago dinner with the prime minister following his election victory.

Trump’s comments are the latest in a back-and-forth spat between the two leaders since the incoming U.S. President made his tariff pledge.

According to Trump, tariffs on Canada and Mexico will be among his first executive orders once he takes office on January 20, 2025.

Alberta Premier Danielle Smith alluded to the threat of tariffs in her own statement on Trudeau’s resignation, which she labelled “selfish.”

“At this critical time, Canadians need and deserve a prime minister and federal government with a clear mandate won from the Canadian people to negotiate with the incoming U.S. President and his administration on one of the most important international negotiations we have ever faced as a country,” said Smith.

“The Liberal Party has no such mandate from Canadians and they are putting their selfish political interests ahead of the Canadian people by paralyzing Parliament and suspending democracy for months while they fight a divisive internal leadership contest.”