Putin’s new tactics are blurring the red line between war and peace

When balaclava-clad French soldiers boarded a tanker off Saint Nazaire, they were not only seizing a vessel in Vladimir Putin’s shadow fleet but also rewriting the rules of engagement between Russia and Europe.

The Kremlin’s confrontation with Nato’s European allies has emerged from the shadows to become an open and relentless campaign of disruption, intimidation and sabotage. Putin’s goal is to inflict as much damage as possible on his adversaries while staying just below the threshold of all-out warfare.

But where exactly is that line? What is the distinction between peace and war? Every time a Russian drone enters European airspace or forces the closure of a European airport, Putin is testing where that boundary lies and probing just how far he can go.

France’s decision to seize the tanker in the Bay of Biscay on Wednesday was designed to change the rules by imposing a limit on Putin’s actions. The vessel, flying the flag of Benin, had not only been part of the “shadow fleet” carrying sanctions-busting oil; it had also allegedly been used to launch the drones that penetrated Danish airspace last month and forced the closure of Copenhagen Airport.

The French operation was supposed to deliver an emphatic message: if Russia uses tankers as drone carriers, then soldiers will board the offending vessels. The idea is to show Putin that he has reached the line where his adversaries are prepared to use force. Having discovered that boundary, he will draw back - or so runs the hopeful theory.

Yet the situation is not that simple. In a confrontation of this kind, action and inaction both send messages. When the drones were in its skies, Denmark decided not to shoot them down in case some crashed in populated areas. France has now seized the alleged mothership for this attack.

Putin might put these facts together and conclude that his adversaries will tolerate the intrusion of drones - even if they close down international airports - provided he does not launch them from ships.

And even if France was willing to board a vessel, suppose the tanker had been off the coasts of Belgium or Holland. Would they have acted?

Putin will have noticed how his shadow fleet tankers, numbering at least 600, have been using European shipping lanes for years without interception. Every day, about 15 of these vessels steam past the white cliffs of Dover and into the Channel.

None has been boarded, sending the implicit message that as long as the shadow fleet sticks to breaking the West’s sanctions on Russian oil and avoids launching drones, its presence will be tolerated.

Nato was founded to deter Russia from invading European countries by sending massed armoured divisions across a frontier. There is an agreed response to obvious aggression of this kind. The country under attack would invoke the mutual defence clause, Article V, of Nato’s founding treaty and every ally would then use force to repel the onslaught.

But Nato has no clear response doctrine for the kind of aggression that Russia is now perpetrating. Instead, incident by incident, that doctrine is being written. Whenever the allies act - or decline to act - the new and usually implicit rules of engagement are being formulated.

So far, Nato has patently failed to deter Putin from waging what experts call a “hybrid” campaign fought in the “grey zone”, just below the threshold of actual warfare. He will almost certainly press on, creating a permanent risk of large-scale casualties in Europe.

Suppose Danish forces shoot down the next Russian drone that violates their airspace, but the object crashes in a busy street and kills a dozen people. What if a shadow fleet tanker creates an environmental disaster by spilling its oil in the Channel - whether accidentally or not - and contaminating a large expanse of the British coastline? What would be the right response?

It will take more than a single French boarding operation to deter Putin. European allies will need to show they are prepared to enforce boundaries by taking calculated risks, seizing ships and shooting down drones as necessary. Otherwise, they unwittingly invite Russia to climb higher up the escalatory ladder - and the risks will only become greater.