Open this photo in gallery:

Demonstrators attend a ‘Defend the Vote’ rally on Aug. 28. American support for tariffs on Canada is split down, and even within, party lines, the Angus Reid polls indicate.Andrew Harnik/Getty Images

At the Korean War Veterans Memorial, just a short walk from the White House on the National Mall in Washington, the names of both Canada and the United States are inlaid in silver.

The memorial, dedicated to those who served in the Korean War of 1950–53, is a testament to the shared cost of the conflict. Nearly 27,000 Canadians served as part of United Nations forces in Korea, alongside millions of Americans. Five hundred and sixteen Canadians died during the war, making it Canada’s third-bloodiest overseas conflict, after the two World Wars.

Along the monument’s granite expanse, listing 22 countries that participated, the names “Canada” and “The United States” stand at opposite ends.

The gulf, at this moment, seems emblematic of another divide: how much citizens of each country are thinking about their relations with the other, a few days after trade negotiations broke down. The Americans visiting the memorial on a recent evening appeared to be thinking very little about the subject.

Opinion: Americans don’t understand Trump’s trade war against Canada. Here’s how to explain it to them

“Our relation to Canada is just not at the forefront of my mind,” said Ryan Finnegan, of Maryland, out for an evening stroll near the monument. “No offence to Canada. It’s just on the back burner when it comes to what I think about.”

Just more than half of Canadians said they are following the tariff threats “closely,” compared with fewer than one-quarter of Americans, according to surveys conducted by Angus Reid in July and August. One-quarter of Americans said they hadn’t heard about them at all.

Meanwhile, only 45 per cent of Americans said they have heard of Mark Carney, according to data-analytics firm YouGov.

Mr. Finnegan did hear that President Donald Trump had made an executive order to rename Lake Ontario to Lake America. But he didn’t pay the announcement too much mind.

“It’s probably going to be gone within two years,” he said, referring to the next presidential election.

“I haven’t heard too much,” Fernando Pech, who is visiting D.C. from outside Sacramento, Calif., said of the rift between the two governments. “I thought they had settled it.”

That’s not to say he hasn’t noticed the pinch of inflation lately: His family of four is dining out less frequently, as the bill regularly exceeds US$200, on top of pricier gas.

Trade talks collapsed suddenly on Aug. 21, with each country’s representatives later pointing the finger at the other over last-minute demands. In response to Mr. Trump’s imposition of 50-per-cent tariffs on about $28-billion of Canadian goods, Ottawa’s dollar-for-dollar countertariffs are scheduled to take effect Sept. 8.

The trade rift is deepening as the U.S. economy is feeling the strain of its conflict with Iran, particularly at the gas pumps.

To First Nations that named Lake Ontario, Trump’s threat doesn’t hold water

Among those paying attention, surveys show American support for tariffs on Canada is split down, and even within, party lines, the Angus Reid polls indicate. While seven in 10 self-described “MAGA Republicans” back Mr. Trump’s tariffs, non-MAGA Republicans are more split, with about one-third supporting them and one-quarter unsure. Democrats are almost universally opposed, with just 5 per cent supporting the tariffs.

Mike McGhee, a local tour guide, was waiting in the centre of the memorial by the American flag – at half-mast, in memory of Dolly Parton – for a group he was showing around. He wasn’t familiar with the new round of threatened tariffs. “I’ve been on vacation. But my wife said there’s been something going on with Canadians and the news recently,” he said.

On the President’s renaming of the lake, he said: “We shouldn’t be renaming anything. How about getting the economy going? How about we leave Canada alone?”

The memorial was busy that night. After a steamy August day, Washington was starting to cool down. Occasionally, police cars rolled by, lighting up the stone and trees in blue, white and red.

Most visitors to the Korean War monument aren’t aware of Canada’s contribution to the conflict, Mr. McGhee said.

“I don’t know if it’s public knowledge that we worked hand-in-hand with these other countries,” he said. “This is just so about America that you kind of forget. Even in the World Wars. We were working with 20 other countries, not just one.”

Nearby, Josh Sefcik was wearing a glowing vest to identify him to his cohort of a few dozen tourists, who were wandering around the reflecting pool.

“Nobody has ever asked me specifically why Canada is here,” he said. “I bring up the United Nations wall when we walk along it,” he added, gesturing to the list of countries that participated in the conflict. “There should be more awareness.”

Gulf of understanding: The way we see the Earth has never been set in stone

The next day, protester Tim Milligan, from Glen Burnie, Md., stood near the White House holding a sign covered in complaints about the Trump administration. At the bottom, in capital block lettering, was the newest addition: “Canada??!! Really?!!”

“The borders have been open, and things go back and forth. As far as I know, it’s been good. No one else has complained in the past,” he said. “Tariffs? We’ve never done this before, not to this extent.”

Despite the current tension, he believes the relationship between the two countries will improve if there’s a shift in U.S. leadership.

“Once Trump is gone and MAGA is dead, things will go back to normal,” he said. “It’s all Trump. Americans love Canada.”