They would have heard those boos right in the Oval Office in Washington, D.C., which is poignant because that’s what the sold out crowd in Montreal were intending happen on Saturday night.

People went to a hockey game and a war broke out.

Not since the British troops set fire to the White House in 1814 has there been this much animosity between these two countries.

This time the battle was on ice. And what a battle it was.

The people in the stands at the Bell Centre were a part of it.

Before the booing, UFC legend Georges St. Pierre introduced the team to loud cheers from the crowd.

But as Warrant Officer David Grenon of the Royal Canadian Air Force Band belted out the Star-Spangled Banner, the sound of boos could be heard from the top of the arena.

Montreal Gazette columnist Stu Cowan reported, “American national anthem” was “booed loudly from beginning to end.”

The Ottawa Sun‘s Bruce Garrioch also shared the booing of the anthem from his perch high above the rink.

It was harder to hear on the Canadian broadcast, but it was unmistakable for those in the barn — including the look on the face of Maple Leafs captain Auston Matthews of the American squad.

So much for being “classy” as retired general Rick Hillier suggested before the game.

This was the opposite of classy — especially when one of our servicemen is in unform doing the singing.

It set a miserable tone for the start of the 4 Nations Face-Off game which saw three fights in the first nine seconds.

But this was more than a hockey game. This was the opening front for the trade war brewing between the U.S. and Canada.

And a massive message to U.S. President Donald J. Trump and his constant narrative that Canada should become America’s 51st state.

And that Canada is not a viable country without the U.S.

He heard it loud and clear. Most Canadians want no part of it. That’s now on the record.

But what is also on record is the American national anthem was disparaged on our Flag Day and the damage for that will not be forgotten south of the border for a long time.

They won’t be happy.

And who knows if there will be retaliation.

It was interesting to see O Canada — led by Prime Minister Justin Trudeau and who Trump rudely refers to as “Governor Trudeau” — was sung loudly and proudly.

It will be interesting to see how American fans respond if Canada ends up playing their next game in Boston.

Will they reciprocate or take the high road?

There is great debate on whether or not this is appropriate. Interesting perspectives on both sides.

“I don’t know about you, but MY Team Canada doesn’t boo the Star-Spangled Banner or any other country’s national anthem during sporting events,” one person wrote on social media site X. “It’s classless and disrespectful and super embarrassing for all Canadians. That is not who we are.”

Former NHL referee Tim Peel called the booing “disrespectful and disgraceful” while Barstool Sports called the fans “scumbags” for not showing respect.

“That just shows you how passionate Canadians are about our country and what the USA president is trying to do,” Dan Jones wrote in a reply to Peel’s post.

“The boos are for Trump not the anthem.”

Toronto lawyer Greg Gilhooly said there is no need to chastise fans who are responding to Trump’s repeated comments that Canada be the 51st state.

“In what world is it appropriate to scold people for booing an anthem in the midst of that nation’s leader name-calling our leader while publicly declaring that our people would gladly welcome becoming the fifty-first state? Booing is nothing more than rebutting the false claim.”

But I always go by the old adage that you can’t expect respect if you don’t offer any.

The fans in Montreal were disrespectful to our American neighbours and there is no getting around that fact. It was not subtle.

Perhaps for some it feels good to be able to stand up and be heard.

But the question may later be asked, at what price?