If it’s too soon to start considering the prospect of France leaving the EU — Frexit — the EU elections are already shaking up French domestic politics. That’s even though the rightward shift of Europe’s voters hasn’t upended the parliament at Strasbourg — where centrist parties look likely to hold control. This is because of President Macron’s gamble — a snap election to, en effet, see if French voters were bluffing by backing right-wing parties. 

Mr. Macron — perhaps in a fit of pique — dissolved the National Assembly after the French handed him what Bloomberg News calls “a severe blow” in the voting for the EU legislature. France’s parties of the right, led by Marine LePen’s National Rally, earned some 37 percent. The support for Mr. Macron’s party amounted to less than 15 percent. He anticipated, Bloomberg said, that France would “make the most just decision for itself and for future generations.”

If Mr. Macron thinks this means French voters will reward him for his fondness for the continental superstate — evidenced by his choice to play the EU’s anthem, and not France’s own, at his first inaugural in 2017 — it could prove a miscalculation. Mr. Macron has long sought to contrast his “pro-European message,” as the Guardian put it, with the right’s “narrow nationalism.” French voters appear less and less receptive to this rhetoric, though.

New polling suggests the National Rally has the backing of 34 percent of French voters ahead of the snap election called by Mr. Macron, versus but 19 percent for his own party. If such polling proves accurate it could give the National Rally the most seats in the French legislature, putting the party in the driver’s seat when it comes to the choice for a prime minister, and raising the prospect of a power-sharing agreement of sorts with Mr. Macron.

The French left is pulling out all the stops to bar this outcome, calling for a 1930s-style “Popular Front” to unite the liberal parties against the right. “To avoid the worst, to win,” is how one leftist politician, Francois Ruffin, explains it. Yet the attempt to isolate the right — a perennial tactic in France — “may not work this time,” the AP reports. That’s because the National Rally “secured more than 10 times the seats it won five years before” in recent elections.

It’s a reminder that the National Rally can no longer be derided as a fringe movement. If the party itself hasn’t moved to the political center, it could be said that French voters themselves have moved toward the party’s viewpoints — on the EU, migration policy, and on the future of the French nation itself. The party’s young leader, Jordan Bardella, a Le Pen disciple, speaks of transforming the country’s politics, the Times reports, to prevent its “disappearance.”

“We have the courage,” Mr. Bardella declares, “to say that if France becomes the country of everyone, it will no longer be the nation of anyone.” Besides lamenting the dissolution of national borders and identities into the EU’s aspirational “ever closer union,” he denounces “the deregulation of migration.” He gives voice to fears, too, about “totalitarian Islamism” gaining a foothold in France “to conquer it, in order to impose its laws and morals.”

Mr. Bardella’s concerns appear to reflect a groundswell of opinion not just in France, but across the continent, where right-wing and Euroskeptic parties surged in the legislative elections. Frustrations over the EU’s inability to defend its borders from migrants were among the animating factors, alongside voter weariness with “virtue-signaling flights of fancy such as net-zero carbon emissions,” as a Wall Street Journal editorial put it.  

Which brings us back to the possibility of a Frexit if Mme. Le Pen’s party gains in the coming vote. During her last presidential bid, she backed staying in the EU but boosting French sovereignty and laws within the context of membership. “Frexit in all but name,” it was called. Her defeat to Mr. Macron forestalled that possibility. Now that the voters will get another chance to speak, though, prospects are looking up for reviving De Gaulle’s “certain idea of France.”