Canadian Prime Minister Justin Trudeau speaks during the Canada Day show on Parliament Hill in Ottawa on Saturday. (Justin Tang/The Canadian Press via AP)

Simply listing all 50 U.S. states would make for a tedious Fourth of July speech, at best. But the concept appealed to Prime Minister Justin Trudeau for his big Canada Day address on Saturday: He would name each province and territory of Canada — with gusto.

After all, there weren't that many of them. How badly could it go?

The prime minister stood before a crowd in Ottawa, waved his arm and began in rapture: “British Columbia!”

Trudeau waited a moment for the applause to stop. Then on to “Yukon!” and “The Northwest Territories!”

That was a nice touch. The sparsely populated northern territories tend to get overlooked, but Trudeau was going geographically, from west to east.

“Saskatchewan!” he said. Hmm. Technically, Alberta would come first, but —

“Manitoba!” Wait, stop.

But Trudeau continued, all the way to the eastern coast of Newfoundland and Labrador, then added: “We embrace the diversity while knowing in our hearts that we are all Canadians.”

An announcer would have to point out that he had forgotten Alberta.

Twitter has not yet stopped reminding him.

Trudeau awkwardly walked back onto the stage after finishing his speech and realizing what he'd done.

“I'm a little embarrassed. I got excited somewhere over the Rockies,” he said. “Alberta, I love you. Happy Canada Day!”

But of all his country's 13 provinces and territories, Trudeau may have forgotten the one least likely to forgive him.

Some reminded the prime minister that his father, Pierre Trudeau, had been widely loathed in Alberta in the 1980s, when he led Canada and forced federal energy policies on the oil-rich province, as the Canadian Broadcasting Corp. reported.

The mayor of Calgary, Alberta, at the time coined a phrase that became a popular bumper sticker across western Canada: “Let the eastern bastards freeze in the dark.”

Decades later, Global News noted, Alberta is a stronghold of opposition to the younger Trudeau and his Liberal Party.

Witness Michelle Rempel, a Conservative member of Parliament representing Calgary, who got on Facebook soon after Saturday's speech.

“The prime minister of our country — on Canada Day! — forgot that Alberta exists,” she said. “I don't think this was an accident.”

Rempel was not alone in her suspicions.

It took no time for Albertans to remember a previous mini-scandal, long before Trudeau became prime minister, when he blamed Canada's woes on “Albertans who control our community and socio-democratic agenda.”

He said this in French, as CBC reported, and added for good measure that all the best prime ministers hailed from Quebec.

So does Trudeau. And when he began his own ascent to the country's highest office in 2012, his campaign tried to explain away that old interview.

“Justin knows that Calgary, Alberta and all of Western Canada are at the very heart of Canada's future,” reads the statement. “We need to get beyond the divisive politics of the Conservatives and include all Canadians.”

So he said, and became prime minister of all Canadians. Then, in a speech on the country's birthday, he forgot about 4 million of them.

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