DEAR READER,

This week's Expert Opinion features a newly-published article by Ana Pisarenco exploring what a Russian test of NATO might entail. Don't miss it!

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Enjoy reading this week’s “brief”!

— Giorgi Beroshvili, Editor

The CIA director’s unusual trip to Moscow came amid warnings that Russia could challenge the Alliance without starting another conventional war. Along NATO’s eastern flank, repeated incidents are already revealing how governments respond when Russian intent is difficult to establish.

When does an incident become a NATO test?

Keir Giles, a British specialist on Russian security policy and European security, is an associate fellow with Chatham House’s Russia and Eurasia Programme. He previously worked at the UK Defence Academy on Russian military, defence and security issues and has written extensively on Moscow’s relationship with the West.

Giles believes Russia has already been learning from the hostile activity directed at Europe. Moscow, in his assessment, would have little reason to risk an unmistakable confrontation with NATO unless it first had some confidence that the alliance would fail to respond as one.

“Russia will not move against a NATO country in an overt and unambiguous way unless it is confident that NATO as a whole is not going to respond,” Giles said. “There is only one way of establishing that confidence, and that is by testing.”

Sabotage, arson, drone incursions and other hostile activity can show how governments react, how quickly responsibility is attributed and whether an incident regarded as serious in one capital produces the same urgency elsewhere.

“The consistent sabotage and drone attacks are alarming, but there is no consensus over how to respond,” Giles said. “So in that respect, Russia has already succeeded.”

Claudiu Degeratu sets the threshold higher. A Romanian security and defence expert, he previously served as director general for defence policy and planning in Romania’s defence ministry and headed the defence section of Romania’s permanent delegation to NATO in Brussels.

“It has tested certain aspects militarily and operationally,” Degeratu said. “It has not tested NATO as an alliance at the level of decision-making cohesion.”

Giles and Degeratu differ mainly over the point at which observation becomes a test of the alliance itself. Giles includes what Moscow can learn from repeated hostile activity and the uneven responses it produces. Degeratu places the threshold at an episode that forces the allies to make a difficult political decision together.

What Romania’s drone incidents reveal

Romania provides a particularly visible record of what can be observed before an incident reaches that point. By August 28th, its defence ministry had recorded 43 unauthorised drone entries since the beginning of Russia’s full-scale invasion of Ukraine, including 25 in 2026. Four drones had been shot down this year, while the ministry’s dashboard listed 84 aircraft deployments for air-policing missions since the war began.

Official statements after individual incidents can disclose when an aircraft was detected, where it travelled and when air-policing procedures were activated. Civilian warnings provide another public record. Read across several episodes, Degeratu said, those details allow an observer to reconstruct parts of the response, from detection and tracking times to the speed with which authorities move to protect the population.

Political decisions are visible too. Emergency meetings, official statements and the point at which an incident is taken to NATO offer indications of how seriously a government regards the threat. Degeratu identified consultations under Article 4 of the North Atlantic Treaty as one particularly revealing threshold.

Article 4 allows a member to request consultations whenever, in its judgement, its territorial integrity, political independence or security is threatened. It does not require casualties, physical damage or proof of hostile intent, nor does it prescribe what the alliance must do afterwards.

Poland invoked the provision in September 2025 after Russian drones violated its airspace, followed later that month by Estonia after Russian fighter aircraft entered Estonian airspace. NATO responded to the Polish incident by launching Eastern Sentry, reinforcing air defence and surveillance along the eastern flank, and now says publicly that Russia has been testing its “resolve and responsiveness” in the region for years.

Degeratu is nevertheless reluctant to treat every Russian drone crossing an allied border as deliberate reconnaissance. Some aircraft have been damaged during attacks on Ukraine or travelled uncontrolled after being hit, and he said there was not enough information to establish a pattern in which every incursion had been designed as a test. A drone travelling deep into Romanian territory along a sustained route would raise different questions from one that fell shortly after crossing the border.

Even an accidental incursion leaves a record. Radar tracks the aircraft, fighters may be sent up, civilians can be warned and officials decide what to disclose. Moscow can observe that sequence whether or not the incident was deliberately created to produce it.

The harder judgement begins when the matter moves beyond the state directly involved. Allies may agree that an airspace violation occurred while differing over whether it was deliberate, how much evidence is needed before responsibility is assigned publicly and what kind of response is justified.

Degeratu described an Article 4 discussion in such circumstances as “the psychological moment when the Alliance has to demonstrate a certain degree of cohesion and solidarity”.

A more demanding case, he suggested, might take the form of a major cyberattack that was serious enough to require a collective response but still remained below the threshold of conventional war, leaving allied governments to act before attribution was fully settled.

To find out why Washington’s role would matter the most, continue reading on our website.

— Ana Pisarenco, a journalist based in Moldova