Poland Has Invoked NATO’s Article 4. What Comes Next?

Poland invoked Article 4 of NATO’s treaty on Wednesday after the alliance’s fighter jets shot down Russian drones that entered its airspace in the early hours of the morning. Russian drones have crossed into Poland before, including twice last week, but this was the first time that Russian drones had been shot down over the territory of a NATO country.

“What is clear is that the violation last night is not an isolated incident,” said Mark Rutte, NATO’s secretary general. “We will closely monitor the situation along our eastern flank, our air defenses continually at the ready.”

Here’s what to know about NATO’s Article 4.

What is NATO?

NATO, the North Atlantic Treaty Organization, is a mutual-defense alliance created after World War II by the United States, Canada and 10 European countries. The alliance’s core provision, Article 5, refers to its commitment to treat an attack on one member as an attack against all of them. When NATO was created, Article 5 put Western Europe under U.S. protection, as the Soviet Union was cementing its dominance over Central and Eastern Europe.

What is Article 4?

Article 4 allows a member state to start a formal discussion among the alliance about threats to its security. While invoking Article 4 does not commit NATO to any military action, it is a required step toward a NATO decision to invoke Article 5. (An invocation of Article 5 is often assumed to have military implications, but the NATO treaty says only that its members will “assist” the party that has been attacked. This can also mean economic or political action.)

Article 4 states that the alliance’s members “will consult together whenever, in the opinion of any of them, the territorial integrity, political independence or security of any of the parties is threatened.”

Since NATO’s founding in 1949, Article 4 has been invoked eight times. Before Wednesday, the last was on Feb. 24, 2022, the day Russia launched its full-scale invasion of Ukraine.

What will NATO do next?

The joint NATO response early Wednesday showed how quickly the war in Ukraine could escalate into a military confrontation between Russia and NATO.

Mr. Rutte said that the alliance’s air defenses were activated to ensure Poland’s protection. The response included fighter jets and air-defense systems from the Netherlands, Germany and Italy, he said.

“The security situation of our airspace has been stabilized, and ground-based air defense and radar reconnaissance systems have returned to standard operational activities,” the Polish military said on social media.

How long has Poland been a part of NATO?

Poland joined NATO in 1999. As the country re-established democracy after the fall of the Soviet Union, a number of events brought Poland closer to the alliance. The reunification of Germany meant that Poland shared a border with a NATO member, and the formation of the Visegrad Group — a cultural and political alliance that includes Poland, the Czech Republic, Slovakia and Hungary — gave these countries more sway in their push for more integration with the West.

Today, Poland is one of Europe’s biggest defense spenders as a share of national income and has led the push for Europe to do more to build up its military defense capabilities.

Were the drones sent intentionally or was it an accident?

It was unclear if Russia had intentionally sought to expand the conflict. Russia’s defense ministry said it had “not planned” to hit any targets in Poland and suggested Poland was out of range of its drones, which is not true. Belarus, Russia’s close ally, sought to play down the incident. Its military chief, Gen. Pavel Muraveiko, suggested in a video on Instagram that the drones that had crossed into Poland had “lost their course as a result of electronic warfare,” though he provided no evidence.