The United States has suspended its involvement in the Permanent Joint Board on Defense, a critical joint defense forum with Canada that dates back to World War II. U.S. Undersecretary of Defense Elbridge Colby announced the decision on social media Monday, stating the department would "reassess" the forum's benefits.

The move comes amid ongoing friction between the Trump administration and several U.S. allies, who President Donald Trump has frequently accused of not contributing sufficiently to mutual defense obligations. Colby explicitly cited Canada's perceived failure to meet its defense commitments as the reason for the suspension.

"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. He added, "We can no longer avoid the gaps between rhetoric and reality. Real powers must sustain our rhetoric with shared defense and security responsibilities."

This decision marks the latest instance of the Trump administration challenging allies on defense spending and responsibility. Many allied nations have refuted these claims, pointing to increased military expenditures and efforts to enhance regional security. For example, at a NATO summit last year, most member states pledged to increase defense spending to 5 percent of their gross domestic product (GDP).

Canada, under Prime Minister Mark Carney, was among the nations that agreed to boost defense spending. Carney's government committed 3.5 percent of GDP to bolstering Canada's "core military capabilities" and the remainder to security-related expenses, including infrastructure and emergency preparedness.

Since becoming Prime Minister in March 2025, Carney has advocated for reducing Canada's reliance on U.S. military and economic power. He has promoted a vision where "middle powers" collaborate to navigate the current "era of great power rivalry," a concept that implicitly includes major global powers like the United States.

The Permanent Joint Board on Defense has historically served as a crucial platform for discussions on continental security and regional defense strategies between the two neighboring nations. Its suspension signals a potential deepening of the strains on the bilateral relationship under the current U.S. administration.

The implications of this suspension are yet to be fully understood, but it raises questions about the future of joint defense initiatives and the broader security architecture between the United States and Canada, particularly given their shared border and longstanding alliance.