The New York Times reported last week on some provocative recent conversations between Donald Trump and Canada’s then-Prime Minister Justin Trudeau, one of which included the American president reading “a long list of grievances.” The Republican, however, also reportedly brought up “something much more fundamental.”

He told Mr. Trudeau that he did not believe that the treaty that demarcates the border between the two countries was valid and that he wants to revise the boundary. He offered no further explanation. The border treaty Mr. Trump referred to was established in 1908 and finalized the international boundary between Canada, then a British dominion, and the United States.

While the Times’ account has not been independently verified by MSNBC or NBC News, Trump has spent parts of this week suggesting the reporting was entirely accurate.

On Wednesday, for example, after hosting an infomercial on the White House South Lawn for his biggest campaign donor, the president set aside some time to pontificate on the border separating the United States and Canada.

After describing the dividing line as “artificial,” the Republican added, “[It] looks like it was done with a ruler, and that’s what it was. Some guy sat there years ago and they said, ‘rah.’”

A day later, as NBC News reported, Trump held an Oval Office event alongside NATO Secretary General Mark Rutte, and again told reporters that he sees the border between the United States and Canada as “an artificial line,” adding, “Somebody did it a long time ago, many, many decades ago, and [it] makes no sense.”

Right around the same time, Secretary of State Marco Rubio was meeting with foreign diplomats at a G7 summit, which is currently being held in Quebec, Canada — a country that Rubio’s boss appears desperate to turn into an American state.

Among the oddities of these developments is how new this is. For all intents and purposes, Trump’s modern political career began when he came down a golden escalator nearly a decade ago, and in the years that followed, he’s never expressed much of an interest in the dividing line between his country and our neighbors to the north.

He didn’t talk about this at rallies; he didn’t publish tweets about it; he didn’t air ads about it; he didn’t invest any energy into this during his entire first term; and he certainly never told voters in any of his three national races that he’d make this a priority. What’s more, it’s not as if there’s a sizable group of voters demanding revisions to the 1908 border treaty.

Nevertheless, just this week, the president twice brought this up unprompted, and according to the Times’ account, he also pressed the same point to the Canadian prime minister during a recent phone meeting.

I haven’t the foggiest idea who put this thought in his head, though it’s worth noting for context that there is another prominent international figure who routinely references an “artificial” line between his country and his neighbor: Vladimir Putin has used the same rhetoric in recent years when describing the border between Russia and Ukraine.