Shopify CEO and co-founder Tobi Lutke threw support behind US President Donald Trump's tariffs, and slammed outgoing Prime Minister Justin Trudeau for not preventing the trade war.

"Canada thrives when it works with America together. Win by helping America win. Trump believes that Canada has not held its side of the bargain," said Lutke, after Trump signed an executive order on Saturday to slap a 25% tariff on America's northern neighbor (10% on oil), citing Canada's failure to help top illegal immigration and fentanyl smuggling, the NY Post reports.

"These are things that every Canadian wants its government to do, too. These are not crazy demands, even if they came from an unpopular source. These tariffs are going to be devastating to so many people’s lives and small businesses," Lutke continued.

Lutke’s withering critique came in response to a clip of Trudeau announcing 25% retaliatory tariffs on $107 billion worth of US goods and pushing for policies targeting red states.

Shopify, the e-commerce giant that Lutke co-founded in 2006, is worth about $150 billion. It’s Canada’s biggest tech company and biggest-ever startup — and second only to the Royal Bank of Canada in size.

Lutke, who's worth an estimated $10 billion, said that "Leadership is about doing what’s right, not what is popular. And hitting back will not lead to anything good. America will shrug it off. Canada will decline."

"It’s simply the wrong choice in a possibility space where much better options would have been available," he continued.

Following Trump's tariff announcement, Trudeau told Canadians that tough times lie ahead for their largest trading partner.