The Trump administration for months blocked a $4.7bn publicly owned bridge between Detroit and Windsor, Ontario, a move critics allege is a quid pro quo for a billionaire Donald Trump donor.

A ribbon-cutting ceremony for the Gordie Howe international bridge connecting Detroit and Windsor was initially scheduled for early June but was abruptly cancelled amid dispute between US and Canadian officials. On 10 July, Canada announced it reached a deal with the US, and the bridge will open on 27 July.

The delay was heavily scrutinized by Democrats, including Rashida Tlaib, a US representative, who said the Trump administration blocked the bridge’s opening as a favor to a donor who owns a nearby bridge.

Canada paid for the Howe’s construction, and it will be jointly owned and operated by Michigan and the Canadian government. It was first set to open earlier this year after eight years of construction.

The new deal requires US government approval if toll fees are lowered below regional averages, according to media reports. Previously, the Canadian government set toll prices, but the Trump administration seemed set on protecting a nearby bridge owned by Matthew Moroun, a son of the late transportation and real estate scion Manuel Moroun.

The younger Moroun owns the nearby Ambassador Bridge, which is North America’s busiest international crossing, and has for decades fiercely opposed plans for the new bridge because he stands to lose business.

As many as 3m trucks cross the Detroit River via the Ambassador bridge annually, and Moroun collects up to $100 on each. But the 93-year-old bridge is often heavily congested with truck traffic that causes extremely long delays that slow and frustrate businesses conducting international trade.

The delays have gotten so bad that many truckers and others use a nearby tunnel, or a bridge in Port Huron an hour to the north. The bridge has also been cited for safety violations in recent decades and its narrow lanes are considered a danger for first responders.

The Howe was envisioned as a symbol of the US and Canada’s close bond, but instead has become a representation of US foreign relations dysfunction. Moroun has capitalized; over the last two decades, his family has mounted multi-prong attacks against the new plans, and is a prolific campaign donor at the state and federal level.

Moroun donated $1m to a Trump political action committee (Pac) in January, and in February received a meeting with Howard Lutnick, the US commerce secretary. Hours later, Trump on Truth Social threatened not to open the Howe. June’s deadlines for an opening passed.

The appearance of a political favor has drawn bi-partisan criticism and an investigation from the House oversight committee members Robert Garcia and Tlaib, whose district includes south-west Detroit, where both bridges sit. A letter the Congress members sent to Moroun accuses him of trying to “derail the project”.

“It appears that you may have used your influence as a donor to President Donald Trump to jeopardize American commerce to protect your company’s bottom line,” the February letter states. Tlaib did not immediately respond to a request for comment, nor did Moroun’s Detroit International Bridge Company (DIBC) or the White House.

The bridge has become fodder for political attacks by Democrats on Republicans. Abdul El-Sayed, the frontrunner in the race for the Democratic nomination for an open US Senate race, linked it to GOP frontrunner Mike Rogers, calling it in a campaign video “A sordid taleof collusion, of corruption.”

For the bridge to open, the federal government must staff the US entry plaza at the Howe, and Markwayne Mullin, the DHS secretary, told the Senate appropriations committee on 13 June: “We have the personnel dedicated, ready to move.”

In February, a Trump spokesperson told the Detroit Free Press the president “has consistently and vocally stood up for American interests – including against Canada”.

Trump at the time wrote on social media that the “US should own half the project” and pledged to block its opening “until the United States is fully compensated for everything we have given” Canada

But the US already owns half the project. Canada paid for the Howe, and Michigan and Canada, under a deal signed in 2012, agreed they would jointly operate it. They would split toll revenues 50-50 after Canada is paid back.

The fight comes amid a broader trade fight between the US and Canada, and may be a chip in that, observers say. Trump did not renew the US-Mexico-Canada Agreement by a 1 July deadline, and tariffs and other trade issues have generated friction.

Trump, administration officials, and Trump allies in Michigan have made outlandish suggestions about what it would take to open the bridge, including extra fees on Chinese cars. Trump bizarrely claimed in February that China would “terminate all ice hockey in Canada” and cancel the Stanley Cup.

Democrats have berated state Republicans and Trump allies for supporting the plan and used it as a campaign attack as the 2026 midterms approach in this critical upper-midwest swing state where the president has won twice, and lost once. In a statement to the Guardian, Curtis Hertel, the Michigan Democratic party chair, called it “Trump’s plan to sabotage Michigan’s economy”.

Adding: “Trump’s chaos will lead to higher costs, fewer jobs, and greater uncertainty for our state’s auto industry—and Michiganders won’t forget Republicans did nothing to stop it.”