Article 5: Could the Ukraine war trigger NATO's defence obligations?

How could the Ukraine war trigger NATO articles 4 or 5? And what exactly do they say?

Poland explosion may be false alarm but chance for spillover remains

Crew members look through a crater next to an overturned vehicle at the site of an explosion in Przewodow, a village in eastern Poland near the border with Ukraine, on Wednesday. (Polska Policja/Reuters)

NATO ambassadors held an emergency meeting on Wednesday after a missile strike killed two people in Poland and raised global alarm that Russia's war in Ukraine could spill into neighbouring countries.

What happened

NATO said an investigation was still underway but the explosion at a grain facility in NATO-member Poland near the Ukrainian border was likely caused by a Ukrainian air defence missile, and there was no indication of a deliberate attack or that Russia was preparing military actions against its allies.

NATO Secretary General Jens Stoltenberg said in Brussels that the attack was not Ukraine's fault and Russia bore ultimate responsibility as it pursued its war against Ukraine.

Polish Prime Minister Mateusz Morawiecki said Poland was still analyzing the possibility of launching an Article 4 procedure — a formal call for consultations among members of the alliance in the face of a security threat — but also said that it seemed it may not be necessary.

Prime Minister Justin Trudeau told reporters on the sidelines of the G20 summit in Bali, Indonesia, that there must be an investigation into what happened and no escalation, but said Russia bears the blame for starting the conflict.

"This had to be an error of some sort, whether it was an errant Russian missile or a Ukrainian counter-missile," said Andrew Rasiulis, a defence expert and fellow with the Canadian Global Affairs Institute.

"The fact is that Russia has zero interest in causing a Third World War between Russia and NATO, which would almost certainly be nuclear."

WATCH | No deliberate attack against Poland, says NATO chief:

No deliberate attack against Poland, says NATO chief

4 months ago
Duration 0:52
An explosion that killed two Polish people near the border with Ukraine on Tuesday was likely caused by a Ukrainian air defence missile trying to intercept Russian cruise missiles, said NATO Secretary General Jens Stoltenberg.

What is Article 4?

Article 4 states NATO members will consult together whenever, in the opinion of any of them, the territory, political independence or security of any of them is threatened.

Under Article 4, discussions at the North Atlantic Council — NATO's principal political decision-making body — could potentially lead to some form of joint decision or action.

Since NATO's creation in 1949, Article 4 has been invoked seven times, most recently in Feb. 2022 when eight members sought consultations following Russia's invasion of Ukraine.

"This is nothing to do with Article 5, where there's actually a deliberate attack against a NATO member, and then the alliance has to deal with a response to an attack," Rasiulis said. "That's war."

WATCH | Rasiulis explains Article 4:

NATO'S Article 4 explained

4 months ago
Duration 1:10
Article 4 of NATO's founding treaty means allies may consult with one another if they feel they're in a potential threat situation, says Andrew Rasiulis, a fellow with the Canadian Global Affairs Institute.

Kerry Buck, a former Canadian ambassador to NATO, agreed that a military response is off the table.

"I'm honestly surprised it took this long for an accident to happen," Buck told CBC News Network. "And NATO's probably looking right now at how it can reduce that risk, if that's possible at all."

What is Article 5?

If Russia were determined to have attacked the territory of a member state, the focus would then shift to Article 5, the cornerstone of the founding treaty of NATO.

The alliance was created in 1949 with the U.S. military as its powerful mainstay essentially to counter the Soviet Union and its Eastern bloc satellites during the Cold War.

The charter stipulates that "the Parties agree that an armed attack against one or more of them in Europe or North America shall be considered an attack against them all."

"They agree that, if such an armed attack occurs, each of them, in exercise of the right of individual or collective self-defence recognized by Article 51 of the Charter of the United Nations, will assist the Party or Parties so attacked by taking forthwith, individually and in concert with the other Parties, such action as it deems necessary, including the use of armed force, to restore and maintain the security of the North Atlantic area," it says.

Police officers in raincoats search and patrol around the blast site in Przewodow on Wednesday. (Omar Marques/Getty Images)

How could the Ukraine war trigger Article 5?

Since Ukraine is not part of NATO, Russia's invasion in February did not trigger Article 5, though the United States and other member states rushed to provide military and diplomatic assistance to Kyiv.

However, experts have long warned of the potential for a spillover to neighbouring countries on NATO's eastern flank that could force the alliance to respond militarily.

Such action by Russia, either intentional or accidental, has raised the risk of widening the war by drawing other countries directly into the conflict.

Buck said she's been impressed but not surprised by NATO's "deliberate and calm" response to the incident, waiting for the facts on the ground. She noted that the responses from NATO leaders were all aligned.

"It's a really dangerous part of the war because Russia understands it's losing," she said.

WATCH | NATO chief pressed on more air defence for Ukraine:

NATO chief pressed on more air defence for Ukraine

4 months ago
Duration 1:40
NATO Secretary General Jens Stoltenberg, responding to a Ukrainian reporter's question, says a meeting will be held today to co-ordinate NATO's layered air defence systems for Ukraine.

Is invoking Article 5 automatic?

No. Following an attack on a member state, the others come together to determine whether they agree to regard it as an Article 5 situation.

There is no time limit on how long such consultations could take, and experts say the language is flexible enough to allow each member to decide how far to go in responding to armed aggression against another.

Article 5 has been activated once before — on behalf of the United States, in response to the Sept. 11, 2001, hijacked-plane attacks on New York and Washington.

What has Biden said about Article 5?

While insisting that the United States has no interest in going to war against Russia, U.S. President Joe Biden has said from the start of Moscow's invasion that Washington would meet its Article 5 commitments to defend NATO partners.

"America's fully prepared with our NATO allies to defend every single inch of NATO territory. Every single inch," Biden said at the White House in September.

He had declared earlier that there was "no doubt" that his administration would uphold Article 5.

A man walks in the lobby of the NATO headquarters in Brussels on Wednesday. (Oliver Mathhys/The Associated Press)

With files from CBC News Network and CBC's John Mazerolle


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