Europe, reacting to “the closest” it has come to open confrontation with a foe since World War II, is consulting over how to react to a Russian drone attack on Polish territory. Will the North Atlantic Treaty Organization do anything beyond the verbal condemnations that have emerged so far?

Poland shot down some of the 19 Russian flying objects that breached its border on Wednesday. A small number of the drones fell on their own, causing no damage. In addition to Polish F-16 fighter jets, Dutch F-35s and Italian AWACS surveillance planes participated in what the Polish prime minister, Donald Tusk, called “the closest we have been to open conflict since World War II.” Speaking at Warsaw, however, he said there was “no reason to believe we’re on the brink of war.” 

The White House, or any other branch of President Trump’s administration, has yet to react to an assault on a fellow NATO member. Poland convened the North Atlantic Council under NATO’s Article 4, which mandates consultations over how to react to a threat. One option — invoking a mutual defense clause under Article 5 — has yet to be triggered by the alliance.    

“Allies expressed solidarity with Poland and denounced Russia’s reckless behavior,” NATO’s secretary general, Mark Rutte, told reporters after a meeting on Wednesday. “A full assessment of the incident is ongoing. What is clear is that the violation last night is not an isolated incident.”

The Russian act, Mr. Rutte added, “intentional or not, is absolutely reckless. It is absolutely dangerous.”

The Dutch, Italian, and also German planes that backed the Polish air force showed that the allies assessed that the Russian attack was an escalation of its European war. It seemed different than past incidents, in which Russian drones or missiles accidentally invaded countries neighboring Ukraine, where the Russians are fighting a war against a non-NATO country.  

Russia denied any involvement, tacitly accusing Ukraine of provoking the incident. “The leadership of the European Union and NATO accuse Russia of provocations on a daily basis,” the Kremlin spokesman, Dmitry Peskov, said. Russian media reports suggested the drones came from the direction of Ukraine. 

President Volodymyr Zelensky vowed to provide NATO with intelligence proving that Russia deliberately attacked Poland. “Previously, there had been cases where Russian drones crossed the border and entered neighboring countries for a short distance,” the Ukrainian president said at Kyiv. “This time we are recording a much larger and deliberate targeting action.”

Russian aggression, Mr. Zelensky added, “poses a threat to every independent nation in our region, and therefore only joint and coordinated action can guarantee reliable security.”