Is Charles going wobbly on Brexit? That’s our concern over the news that Britain’s new monarch contrived to take tea with the president of the European Commission, Ursula von der Leyen. This tête-à-thé was arranged, the Guardian guffaws, “to create the impression” of a “royal endorsement” of Prime Minister Sunak’s new Northern Ireland trade pact. Call it two unelected leaders supping on sovereignty. 

Which looks like trouble to us. This sovereignty question is at the heart of Brexit. We’ve been covering it since before the referendum in which the Britons declared unambiguously for independence from Europe. We editorialized about it months ahead of the vote, when Prime Minister Cameron suggested to the voters that an independent Britain would offer but “an illusion of sovereignty.” Where would that leave the Crown, we wondered.

After all, we argued, the European state’s notion of “ever greater union” is designed “gradually to strangle from its member states any capacity for independent action.” So we were relieved when, three months before the referendum, the London Sun came out with its famous wood declaring “Queen Backs Brexit.” The palace protested, professing neutrality. We called it — and still believe it to be — “Elizabeth’s Finest Hour.”  

The London Sun was quick to note that the palace hadn’t denied the Queen’s comments, yet accepted a slap on the wrist from press regulators, only to double down on its report. “Does the Queen back Brexit? We’re sure she does,” wrote the editors of the London paper. “Having devoted her life to Britain,” the editors added, it was no wonder the Queen felt strongly “about the erosion of our sovereignty by the EU.”

Which brings us back to Elizabeth’s eldest son. We’re a newspaper, not a psychiatrist, so we can’t diagnose what’s going on in His Majesty’s mind. We’re not alone, though, expressing concern about what signal Charles means to send by meeting with the EU chief at such a pregnant political pass. No less a figure than Jacob Rees-Mogg reckons that the teatime parley “antagonizes the people the prime minister needs to conciliate.”

Plus, too, Mr. Rees-Mogg called it “constitutionally unwise to involve the king in a matter of immediate political controversy.” Mr. Sunak, for his part, was keen to frame the meeting as a choice “fundamentally” made by Charles. “It’s for the king to make those decisions,” a Sunak representative allowed. A former first minister at Belfast, Arlene Foster, called the meeting “crass” and contended it “will go down very badly” at Northern Ireland. 

Nigel Farage called it “disgraceful” for Mr. Sunak to have suggested the meeting and wondered “whether the king had to accept.” He suggested Charles “is taking a very big chance” with loyalists among the Northern Irish by sipping Darjeeling with Ms. von der Leyen. “The unionists like the monarchy,” Mr. Farage said, and “they want to like” Charles, yet the meeting will “put the most enormous strain on” their fondness for the new king.

This is all coming to a head over the waters between Britain and Ireland as Britain struggles to extricate itself from the EU’s grip. The land border with Ireland, which remains in the EU, has proven a sticky wicket for Brexit. Mr. Sunak’s “high-risk strategy,” Reuters explains, seeks to curry favor with Brussels by keeping EU regulations intact over Northern Ireland in order to avoid an unpopular hard trade barrier with Ireland.

The EU is luring Britain back with enticements, like, Reuters reports, allowing British scientists, if the deal is accepted, “to join a vast EU research program.” By such inducements, the EU aims to reverse Britain’s vote for independence. On this head we’re disappointed that Charles, whose coronation nears, didn’t show more spine. After all, if Brexit is reversed, he would on May 6 be invested with, to echo Mr. Cameron, an illusion of a crown.