Last year, Russia’s unprovoked invasion of Ukraine dominated NATO’s annual summit in Madrid. This week’s NATO summit in Vilnius, Lithuania, will be even more demanding. This is the first time in its history that NATO’s current 31 members now simultaneously face a bloody war on the eastern border with Ukraine and two aligned, possibly hostile, superpowers with expansive ambitions.

An extraordinary event just occurred in Russia. The head of the Wagner Group, Yevgeny Prigozhin, turned against the Russian military, preemptively sending his forces to within 120 miles of Moscow. His aim was to protest both the derelict way the war was being waged in Ukraine and his disgust with Minister of Defense Sergei Shoigu and Chief of Defense General Valery Gerasimov and the transfer of his group to Ministry of Defense control.  

Within 24 hours the dispute was apparently ended by the intervention of Belarus’s President Alexander Lukashenko. But the consequences are unclear and this bizarre confrontation may not be over. This protest was not an attempted coup, but nonetheless, raises profound issues for NATO. 

Will Prigozhin’s preemptive strike overshadow the summit? NATO planners doubtlessly are focused on analyzing what and why this happened, as well as the consequences for NATO and the “no-limits” Russo-Sino partnership. This will be made more difficult in that NATO has only a few days to sort this out before the summit.

The summit was otherwise concentrating on the formal entry of Finland to the alliance and now the unlikely accession of Sweden given Turkey’s objections. Raising defense spending to meet the 2 percent of gross domestic product goal was on the agenda. And membership for Ukraine will be tempered by promises of support “for as long as it takes,” deferring it until after the war ends and the time is right. Meanwhile, NATO may agree to transfer longer-range fires to Ukraine.

To ease Ukraine’s entry into NATO, as a first step, Kyiv could be invited to join the Joint Expeditionary Force (JEF) — led by the United Kingdom and fellow NATO members Denmark, Finland, Estonia, Iceland, Latvia, Lithuania, the Netherlands, Sweden (awaiting approval) and Norway — de facto or as an observer. However, dealing with Russia becomes the dominant issue. Here are a few realities.

No matter whether Putin remains in power, Russia’s military has been more than decimated in terms of men and material. That means Moscow will have to rebuild its forces. That will take considerable time and money. Remember how long it took the U.S. to recover from the post-Vietnam War “Hollow Force.”

One consequence is that the bulk of Russia’s remaining military strength is nuclear: 1,550 strategic warheads and some 4,500 so-called tactical nuclear weapons. That could lead to a dramatic shift in Russian strategy returning to the earlier days of the Cold War and greater reliance on nuclear weapons. A new arms race could be provoked.

Another possibility, no matter how remote, certainly bears scrutiny. The events appeared staged, contrived and orchestrated. The compressed timetable from the seizure of Rostov on the Don to the end of the crisis and the intervention of Lukashenko could be a coincidence.  

But that may not be the case. Maskirovka, classic Russian and Soviet deception, should not be ruled out. Of course, one counterargument — the Wagner Group shooting down several Russian helicopters as it marched north — suggests otherwise. If this were staged, why would there have been these firefights?

Unknown is the future of Prigozhin and the Wagner Group. Once reported to be in Belarus, Prigozhin may be in St. Petersburg, which would contradict his self-exile. And if he returns to Belarus, what could this mean?

Suppose Putin was indeed desperate to reverse the course of the Ukraine war. An attack by the Wagner Group from Belarus, against Ukraine, would certainly disrupt Kyiv’s offensive. And an attack could cut the logistics lines from Poland on which Ukraine is vitally dependent. Indeed, this strikingly bold scenario is an extension of how “little green men” swarmed into Crimea in 2014.

Further, Putin’s threat to station tactical nuclear weapons in Belarus could have been a precursor for this scenario. With nuclear weapons present in Belarus, would NATO be prevented from taking strong retaliatory action? And do not foreclose Putin engineering some crisis to disrupt the summit.

The summit has been turned on its head by this stunning turn of events. How NATO responds is crucial. Platitudes won’t work. It is time for some very, very serious thinking. But is NATO capable, and at such short notice?

Harlan Ullman, Ph.D., is a senior adviser at Washington, D.C.’s Atlantic Council and the prime author of the “shock and awe” doctrine.  His 12th book, “The Fifth Horseman and the New MAD:  How Massive Attacks of Disruption Became the Looming Existential Danger to a Divided Nation and the World at Large,” is available on Amazon. He can be reached on Twitter @harlankullman.