Just because Canada and the United States worked closely together to restrict travel across their shared border doesn’t mean they were always going to move in lockstep when the time came to reopen it, says Ottawa’s envoy to Washington.

There’s been “enormous” co-ordination and information shared between the two regarding the border since the onset of the COVID-19 pandemic, said Canada’s ambassador to the US, Kirsten Hillman. “But co-ordination doesn’t mean you’re going to do exactly the same thing,” she told a Wilson Center panel discussion alongside interim US counterpart Arnold Chacon on Friday.

It was Hillman’s first public appearance since the US confirmed on July 21 that it would maintain its travel restrictions on non-essential visitors from Canada for at least another 30 days. But her message was the same one she’s been delivering for weeks: that each country would ultimately make its own determinations.

The US decision to extend the travel limits came just two days after Ottawa declared fully vaccinated American citizens and permanent residents would be allowed back Aug. 9, with the rest of the world to follow Sept. 7.

The restrictions have always differed significantly, Hillman noted – Canadian air travellers have always been able to fly to the US, where the bulk of the restrictions apply mainly to land crossings, while Canada has restricted all discretionary travel from south of the border.

“We both are also committed to making decisions based on science and the advice of experts – and those are our experts, our science, our experts, our country, what is happening for us on the ground,” she said, adding, “The US is doing the same: it’s making decisions based on their situation on the ground.”

Chacon, who agreed with Hillman’s assessment of the “stellar” teamwork to date between the two countries, would only say that discussions about the border are ongoing and will continue.

“We continue to review our travel restrictions, and any decisions about reopening travel are going to be guided by our public health and medical experts,” Chacon said from Ottawa, parroting the Biden administration’s position. “We take this very, very seriously. But I think we’re in a good place and the trajectory is very promising.”

Officials at DHS specifically cited the rampant spread of the Delta variant of COVID-19 as part of their decision – which includes Mexico – and promised to keep the lines of communication open.

But the apparent divergence has angered US residents who have been waiting for months for the chance to visit Canadian friends, family, and vacation properties, as well as the members of Congress who represent them.

New York Rep. Elise Stefanik denounced the decision earlier this week as “absolutely and unequivocally unacceptable,” joining a growing cadre of angry US lawmakers that includes Senate Majority Leader Chuck Schumer and the entire congressional delegation for Maine.

Rep. Brian Higgins, a New York Democrat who has led the charge against the restrictions, described himself as “infuriated” with what he called an “incomprehensible” extension.

Border experts say the delay may be related to reluctance to reopen the US-Mexico border, given the existing refugee crisis there, and the fear of political blowback if travel from Canada is allowed a head start.

There’s also the added element of whether or not the US, where only 57% of eligible Americans have had a full course of a COVID-19 vaccine, will make proof of vaccination a condition of entry.

The White House has already made clear it does not support requiring vaccination credentials in the US, a country famous for its fierce guardianship of personal liberties.

John Adams, a Florida resident who owns a vacation property on Vancouver Island, has been crowdfunding a cross-border television and internet ad campaign against the two governments in recent weeks to convince them to lower the barriers.

His latest campaign-style attack ad, which began airing Friday, accuses Biden of “holding Canadian citizens hostage,” complete with famous images of blindfolded prisoners held in Iran during the 1980 hostage crisis there.

At the same time, two Canadian provincial premiers and the leaders of three states have written the heads of their two countries to ask for the move.

The letter, written by Saskatchewan Premier Scott Moe, his Alberta counterpart Jason Kenney, and the governors of North Dakota, Montana and Idaho say the time has come for citizens to be able to move freely over the border to resume trade and tourism. It adds that the current restrictions are unnecessary delays and that the states and provinces are managing their COVID-19 infections.