Trump Threatens to Derail $6.4 Billion Canada-U.S. Bridge, Igniting Trade Firestorm

President Trump threatened on Thursday to block the opening of the Gordie Howe International Bridge, a $6.4 billion megaproject fully financed by Canada, unless the United States receives compensation for what he called “decades of unfair trade practices.”

The threat, delivered in a late-night social media post, caught both Canadian and American officials off guard. The bridge, which spans the Detroit River between Windsor, Ontario, and Detroit, Michigan, is already structurally complete and scheduled to open later this year.

“Canada built a bridge to our country without asking permission,” Trump wrote. “Now they want to use it to flood our markets. Not going to happen unless we get a very big discount on dairy and lumber.”

The post immediately sent shockwaves through cross-border business communities. The Gordie Howe bridge is the largest new trade artery between the two nations in decades, designed to handle up to 40 percent of the $1 billion in daily trade that crosses the Windsor-Detroit corridor.

Canadian Prime Minister Mark Carney responded within hours, striking a tone of measured defiance. Speaking from Ottawa, he emphasized that the bridge is jointly owned by Canada and the state of Michigan—not the federal government in Washington.

“This is not a gift to the United States,” Carney said. “This is an investment in shared prosperity. The bridge will relieve bottlenecks that cost both countries billions annually. Threatening to block it hurts Michigan workers as much as anyone.”

The prime minister’s reference to Michigan was strategic. The state’s governor, Gretchen Whitmer, has been a vocal supporter of the project, which created thousands of American construction jobs and is expected to boost manufacturing supply chains across the Midwest.

By Thursday afternoon, Whitmer issued her own statement. “The Gordie Howe Bridge is a symbol of cooperation, not a bargaining chip,” she said. “I urge the president to reconsider any action that would harm Michigan families and businesses.”

The bridge’s financing structure makes Trump’s threat unusually complex. Canada paid the entire construction cost under a public-private partnership. Ownership is shared with Michigan through a binational authority. The U.S. federal government contributed nothing.

Legal experts quickly noted that the president has no direct authority to close a bridge owned by a state and a foreign nation. However, federal agencies control border crossings, customs operations, and access roads—all of which could be weaponized.

“He can’t literally block the bridge without a court fight,” said Robert Hockett, a trade law professor at Cornell. “But he could slow customs processing to a crawl, restrict commercial truck access, or impose new inspection fees. There are dozens of ways to strangle a bridge without touching it.”

Canadian business leaders reacted with alarm. The Windsor-Detroit corridor is the busiest commercial land border crossing between the two countries. The existing Ambassador Bridge, privately owned, is frequently congested and vulnerable to disruption.

“We have waited twenty years for this bridge,” said Flavio Volpe, president of Canada’s Automotive Parts Manufacturers’ Association. “Every delay costs jobs on both sides. This isn’t a game. This is the literal supply chain for North American auto production.”

The timing could hardly be worse. Automakers are already navigating semiconductor shortages and shifting electric vehicle production. A disruption at the border would idle factories within days.

Trump’s social media post did not specify what concessions he seeks. But his mention of dairy and lumber echoes longstanding American grievances under the United States-Mexico-Canada Agreement, which the president has called “a disaster” despite having signed it.

Canadian officials privately expressed bewilderment. The Gordie Howe bridge was conceived during the Obama administration, negotiated under Trump’s first term, and completed without objection from either side until now.

“We followed every rule, every agreement, every permitting process,” said a senior Canadian official who spoke on condition of anonymity. “And still, at the finish line, the president decides to move the goalposts. How do you plan for that?”

By evening, Michigan’s congressional delegation was scrambling. Republican and Democratic lawmakers alike began drafting a bipartisan resolution affirming the bridge’s importance. The White House did not respond to requests for clarification.

For now, the bridge stands silent, its six lanes polished and waiting. Construction crews have finished landscaping. Toll booths are installed. Signs direct drivers toward an opening date that suddenly seems uncertain.

Prime Minister Carney ended his statement with an unusually personal note. “The bridge is named after Gordie Howe, a great Canadian who became a beloved Detroit Red Wing,” he said. “He crossed borders not to fight, but to play. We should remember that.”

Whether the president is listening remains unclear. But across the frozen Detroit River, two nations are learning again that the longest undefended border in the world can still be closed by a single post.