The ‘shadow war’ denounced by Berlin is already on Europe’s border

To understand what is happening on Europe’s eastern border, it is best to start from Berlin, not from a trench. The head of the German intelligence services, Martin Jaeger, has said that Germany faces a growing risk of violent conflict with Russia and has described Moscow’s actions as a ‘shadow war’: cyber-attacks, drones, sabotage and covert operations. But the perimeter of European security no longer begins when a tank crosses a border: it begins much earlier.

Looking at the map from north to south, the news is striking. In the spring, Russian vessels specialising in submarine warfare were intercepted near Svalbard whilst, according to Western sources, they were simulating an operation against strategic cables. In the Gulf of Finland, at the end of September, Swedish and Finnish fighter jets intercepted Russian military aircraft.

Then there are the Baltic states. By 2026, NATO had transformed its former air policing mission into a genuine air defence posture. Estonia is permanently redeploying its main combat units closer to Russia. The new doctrine is called ‘active defence’: not preparing to lose territory only to recapture it later, but preventing it from being occupied in the first place. This is the most concrete lesson learnt from Ukraine.

At the centre of the story is Kaliningrad, the Russian exclave between Poland and Lithuania – a stronghold of missiles and air defences, but also a vulnerable point because it is separated from the rest of Russia. At the end of September, Moscow warned NATO that it might resort to nuclear weapons if the exclave were to be isolated or attacked. Mark Rutte replied that there is currently no imminent threat of a Russian attack and that an operation against Finland, the Baltic states or Poland would require visible military preparations. This is a crucial point: deterrence does not mean a prophecy of war.

Further south, however, the threats are not merely theoretical. Following several incursions by Russian missiles and drones into Polish airspace, Lublin has reopened a Cold War-era shelter. And in Leipzig, in August, Berlin blamed Russia for an attempted drone attack on the airport.

The Western response has two names: Baltic Sentry and Eastern Sentry. The former protects cables, gas pipelines and underwater infrastructure in the Baltic; the latter reinforces the eastern flank with fighter jets, ships, anti-aircraft systems and anti-drone capabilities. It is an attempt to deprive Moscow of the ‘grey area’ – that zone where an act of sabotage seems too minor to trigger Article 5, and a drone too ambiguous to warrant a response.

Here are the two mistakes to avoid. The first is to portray everything as if a NATO invasion were just around the corner: it is not, according to the Atlantic Alliance itself. The second is to use this caution to conclude that nothing is happening. A great deal is happening: incursions, acts of sabotage, pressure on infrastructure, nuclear threats. This is not a war between Russia and NATO. It is a contest to see how close one can get to war without actually starting one. Deterrence serves precisely this purpose: to prevent ambiguity from becoming an advantage. To make it clear that there is no cable in the Baltic, no airport, no border and no patch of sky so insignificant that it can be violated without consequences.