The aftershocks of European parliamentary elections last weekend are mainly political — Brussels blistered, France aflutter, Germany jarred — but they are also geopolitical. That is because most of the parties often described as “far right” that made big advances on Sunday are unapologetically nationalist. More often than not, that means prioritizing domestic concerns like immigration and the cost of living crunch over support for Ukraine. The populist leader of Hungary and perpetual bugbear of Kyiv, Viktor Orban, noticed.

Not only that, but he has been preparing for the changing currents. So it was without any angst that on Wednesday Mr. Orban struck a deal with the NATO secretary-general, Jens Stoltenberg, to opt out of offering military support for Ukraine. That might not have set off alarm bells at a White House preoccupied with much else right now — at least, not yet.

To be clear, Hungary is not about to impede the Western alliance’s future military aid to Ukraine. Mr. Orban, though, succeeded in preserving Budapest’s right to take its own path. He dropped the hint he would do so last month when he said he wanted to “redefine” the terms of Hungary’s NATO membership because of its opposition to the alliance’s military backing of Ukraine. 

On Wednesday he said that Hungary had obtained “the guarantee today that when it comes to the Russian-Ukrainian war, when it comes to military out-of-area operation, we do not have to participate in that,” adding: “Hungary will not provide funds or personnel for the war, nor will the territory of Hungary be used for any involvement in this war.”

Mr. Orban was clearly emboldened by the recent European election results, saying that they served to reinforce Budapest’s “mandate” to “not participate in a war” outside of NATO members’ territory. A solemn-faced Mr. Stoltenberg, who traveled to Budapest on Wednesday, told reporters, “Prime Minister Orbán has made it clear that Hungary will not participate in these NATO efforts and I accept this position.”

It was a deflating moment for Mr. Stoltenberg, particularly as it came ahead of next month’s alliance summit at Washington. It was also a rebuke of Mr. Biden and his top diplomat, Antony Blinken, under whom the Department of State has taken an undiplomatically antagonistic approach to Hungary. 

If by dint of nothing other than geography, Mr. Orban is more attuned to the vagaries of European sentiment than is that old Cold Warrior, Mr. Biden. In France, the right-wing National Rally is poised to capitalize on its recent European success in the French snap election less than a month away.

That it will snap up enough seats in the French parliament to hamstring virtually anything President Macron wants to do — except, possibly, resign — is a foregone conclusion. Mr. Macron is pro-Ukraine, and if National Rally’s Marine Le Pen is not anti-Ukraine, she is resolutely anti-EU and pro-French identity above all.

Giorgia Meloni may be a supporter of Ukraine and President Zelensky, but the Italian prime minister is surrounded by people like her deputy prime minister, Matteo Salvini, who at least in the recent past has considered himself a friend of Vladimir Putin. Whenever in recent months Mr. Macron has hinted at the future possibility of troops in Ukraine it is the Italians, if not Ms. Meloni herself, who have made the most bones about it.

While Ms. Meloni and Mr. Orban may have divergent views on foreign policy, they tend to be on the same page politically. 

As for the Hungarian opt-out on Ukraine action, it would be a mistake to view it as being of minor consequence. This is despite attempts from some European capitals to ostracize Hungary. 

Consider the Netherlands, where the right-wing Party of Freedom, led by Geert Wilders, made big gains in the European Parliament. 

Now Mr. Wilders wants an opt-out on the EU’s flawed migration and asylum policy. With growing popular support behind him he is likely to get his way as Mr. Orban just got his — and this augurs a general weakening of a unified European response to any number of crises, Russian-related or not. 

Unsurprisingly, this all reflects poorly on Secretary Blinken. His ineffectual policy making on Ukraine may not be as bad as his growing roster of fumbles in Africa and the Middle East, but that is only because he has had sharper minds at NATO headquarters and at Westminster as capable wingmen. The record shows that two wars started on his watch, not that of his Republican predecessors.

For some politicians Mr. Biden’s policy on the Ukraine war has been reactive and reductive — arm Ukraine directly and roughhouse Russia indirectly for as long as it takes — while for others it does not go far enough. More complicated wars, after all, have wound down in much less time. 

Through all the ambiguity and autopiloting, though, Messrs. Biden and Blinken emerge as the somewhat detached co-authors of a toxic muddle in the middle of Europe. So when one of the most stubborn members of  the bloc, Hungary,  gives the White House a rebuff, it can be expected that similar gestures from other foreign quarters will follow. Possibly before November, too.