Washington — Renewed threats from the United States to reconsider its participation in the United States–Mexico–Canada Agreement have unsettled markets and policymakers, reviving questions about the durability of North American economic integration and the costs of trade brinkmanship.

The latest episode began when former President Donald J. Trump, speaking amid broader criticism of multilateral trade arrangements, suggested that the United States could once again walk away from the USMCA if it failed to deliver what he described as sufficient benefits for American industry. While similar warnings have been issued before, officials and analysts said the timing and tone carried added weight.

This time, Canada did not respond with visible urgency. Instead, Prime Minister Mark Carney and senior economic officials emphasized continuity, signaling that Ottawa would not negotiate publicly under pressure. The posture contrasted with earlier periods of trade tension, when Canadian leaders moved quickly to reassure Washington and stabilize markets.

“The message from Ottawa was calm and deliberate,” said a former Canadian trade negotiator. “They weren’t dismissing the risk, but they weren’t reacting to it either.”

Canada’s response reflected preparations already underway. Over the past year, Canadian officials have worked closely with industry leaders to reduce exposure to sudden policy shifts from the United States. That effort has included diversifying export markets, accelerating trade agreements with Europe and Indo-Pacific partners, and encouraging domestic supply chains in key sectors.

While the United States remains Canada’s largest trading partner by a wide margin, the share of Canadian exports destined for non-U.S. markets has gradually increased. Economists note that such diversification does not eliminate dependence, but it can soften the immediate impact of trade shocks.

In Washington, the reaction was more complicated. Lawmakers from manufacturing-heavy states expressed concern that renewed uncertainty could disrupt supply chains already strained by inflation and geopolitical risk. Several business groups warned that even rhetorical threats to withdraw from the USMCA could deter investment.

“You don’t need to tear up an agreement to cause damage,” said an executive at a U.S. manufacturing association. “If companies believe rules might change abruptly, they pause. And when they pause, communities feel it.”

Behind closed doors, U.S. officials acknowledged that pushback from industry was growing. According to people familiar with internal discussions, corporate leaders pressed the administration and congressional offices to avoid escalating rhetoric that could undermine cross-border production networks in autos, agriculture and energy.

The pressure appeared to have an effect. While Mr. Trump continued to criticize the agreement publicly, there were no immediate steps taken to initiate a formal withdrawal process. Analysts described the moment as a familiar pattern: strong threats followed by institutional resistance and eventual restraint.

For Canada, the episode reinforced a broader strategic lesson. Dependence on the U.S. market has long been efficient, but it also leaves Ottawa vulnerable to political cycles in Washington. Mr. Carney, a former central banker, has framed economic policy increasingly in terms of resilience and risk management rather than maximized access alone.

“Integration brings prosperity,” Mr. Carney said recently, “but resilience determines how you weather volatility.”

Market response reflected that assessment. While currency and equity markets registered brief volatility following the remarks, there was no sustained selloff. Analysts attributed the relative calm to expectations that the USMCA would remain intact, at least in the near term, and to confidence that both governments understood the stakes of disruption.

Trade experts caution that the underlying tensions have not disappeared. Disputes over industrial policy, subsidies and regulatory alignment continue to test the agreement’s framework. But they also note that the costs of unraveling North American trade would be borne quickly and unevenly, particularly in border regions.

“The system is deeply intertwined,” said a trade economist at the Peterson Institute for International Economics. “That interdependence limits how far threats can go before they start hurting the sender.”

Whether the latest confrontation marks a turning point or simply another cycle in a recurring pattern remains unclear. Similar episodes in the past have flared and subsided without formal rupture, leaving the agreement intact but trust somewhat eroded.

What appears to be changing is the response. Canada’s steadier posture suggests a willingness to absorb short-term uncertainty rather than concede to pressure. In Washington, resistance from industry and lawmakers underscores the constraints on aggressive trade tactics.

As the political calendar advances on both sides of the border, the episode serves as a reminder that North American trade rests not only on treaties, but on confidence. Rebuilding that confidence may prove more challenging than testing it.

For now, the USMCA remains in force. But the latest exchange has once again exposed how quickly rhetoric can ripple through an integrated economy — and how adaptation, rather than confrontation, is increasingly shaping the response.