What led to Poland invoking NATO’s Article 4 and where could it lead?

After a Russian drone blitz, Warsaw’s rare move to invoke the important NATO statute has potentially moved Europe closer to continent-wide warfare

The Chief of the General Staff of the Polish Armed Forces, General Wieslaw Kukula, talks with Major General Maciej Klisz following violations of Polish airspace during a Russian attack on Ukraine in Warsaw, Poland, on September 11, 2025.
The war between Russia and Ukraine is threatening to spill into NATO member nations
(Image credit: Aleksander Kalka / NurPhoto / Getty Images)

Poland has spent the past several years watching anxiously as its neighbor, Ukraine, fends off an invasion by Russia. But following an incursion into Polish airspace on Wednesday by what Prime Minister Donald Tusk described as a “huge number of Russian drones,” Warsaw has taken the rare step to invoke Article 4 of the NATO charter.

The measure calls for member nations to “consult together” and determine if the “territorial integrity, political independence or security of any of the parties is threatened.” If so, the group can then invoke NATO’s Article 5, which calls for a unified and potentially armed response.

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Rafi Schwartz, The Week US

Rafi Schwartz has worked as a politics writer at The Week since 2022, where he covers elections, Congress and the White House. He was previously a contributing writer with Mic focusing largely on politics, a senior writer with Splinter News, a staff writer for Fusion's news lab, and the managing editor of Heeb Magazine, a Jewish life and culture publication. Rafi's work has appeared in Rolling Stone, GOOD and The Forward, among others.