US suspends joint defence effort with Canada dating back to World War II

The Trump administration has frequently accused US allies of failing to live up to mutual defence obligations.

The United States has said it will not take part in a joint board for continental defence with Canada, depicting the country as failing to live up to its defence obligations.

On Monday, US Undersecretary of Defense Elbridge Colby wrote on social media that his department would halt its involvement in the Permanent Joint Board on Defense to “reassess” the forum’s benefits.

The board dates back to World War II and has served as a forum for regional security. But relations with Canada have grown strained since US President Donald Trump returned to office for a second term in 2025.

“A strong Canada that prioritizes hard power over rhetoric benefits us all. Unfortunately, Canada has failed to make credible progress on its defense commitments,” Colby wrote on X.

“We can no longer avoid the gaps between rhetoric and reality. Real powers must sustain our rhetoric with shared defense and security responsibilities.”

The announcement is the latest instance of the Trump administration chiding Western allies for what the president believes is an overreliance on US military power.

Allied countries have largely refuted his claims, arguing that they are ramping up military spending and taking steps to take greater control over regional security.

Just last year, at a NATO summit in The Hague, nearly every member state agreed to increase defence spending to 5 percent of their gross domestic product (GDP). Spain petitioned to be excluded from the agreement, though.

Canada, under Prime Minister Mark Carney, was among the countries committing to the increased spending.

Of the 5 percent earmarked for defence, 3.5 percent would go to bolstering Canada’s “core military capabilities”, Carney’s government said. The rest would go to security-related expenses, including port improvements, emergency preparedness and other resources.

Since taking office as prime minister in March 2025, Carney has been an outspoken supporter of lessening Canada’s dependence on the US’s military and economy.

In a speech this year, he outlined a vision in which “middle powers” like Canada banded together to sidestep the current “era of great power rivalry”, a veiled reference to countries like the US, Russia and China.

While the US and Canada are neighbours, Trump’s second presidency has resulted in fraying bonds between the two countries, even beyond matters of security.

Trump has accused Canada of pursuing unfair trade policies and failing to crack down on the illicit traffic of people and drugs across the border, though critics have questioned the legitimacy of these claims.

To force Canada to comply with his policies, the US president has pursued an aggressive tariff regimen to tax cross-border imports.

Trump has suggested in the past that Canada could avoid such penalties by ceding its sovereignty and becoming the US’s 51st state.

“Cooler and wiser brains are needed to preserve a close alliance w/ our neighbor,” US Republican Representative Don Bacon said in a social media post on Monday, criticising the decision to pull out of the defence forum with Canada.

“This all started w/ taunts of ‘Canada will be the 51st state’ and ‘their Prime Minister will be the 51st governor’. The insults gained us nothing but animosity that cost us economically and now militarily.”

The US, Canada and Mexico are set to negotiate an updated version of a regional free trade agreement, known as the USMCA, later this year.