Deterrence clearly failed in Ukraine. In the run-up to Russia’s invasion inFebruary 2022, America and its nato allies took steps to warn Russia of dire consequences, including deep sanctions and political excommunication.None of that mattered to Vladimir Putin.
Some argue that nato failed to deter Mr Putin because he has nuclear weapons.The Kremlin’s nuclear sabre-rattling feeds this view, bringing nuclear weapons to public consciousness in a way that they have not been for many years.
And yet, as the war goes on, Russia has indeed been deterred. Although theRussians rage against the arms and equipment that nato countries are sending to Ukraine, they have not once touched nato territory to try to stop the shipments. The Russians brag, often without confirmation, about destroying nato weapons in storage or on the battlefields in Ukraine, but they have not disrupted transit in nato countries.
So Russia and nato countries are equally deterred from direct confrontation, hewing close to the principle that President Joe Biden laid down at the outset of the invasion: the necessity to avoid a general war in Europe that could escalate into global nuclear annihilation. For America and nato, this means assistingUkraine, but not fighting for it. For Russia, it means not striking nato territory.
As the war continues, deterrence is taking on a more nuanced and complex character that bears close watching. Take the efforts to continue grain shipments out of Black Sea ports despite the Russians’ withdrawal from the un-brokered grain deal. When Russia left the deal in July it declared a blockade ofUkrainian Black Sea ports, threatened commercial vessels with attack and began bombing Ukrainian ports, destroying grain silos and infrastructure.
Ukraine responded by appealing to nato allies to support its efforts to ship grain and turning to its ports on the Danube. Although these river ports do not have the capacity of the large Black Sea ports such as Odessa, they do have certain advantages. One is their proximity to the Bosphorus, which shortens the time it takes for ships to exit the Black Sea.
Another is that a nato country—Romania—is right across the river. nato has been alert to Russian missiles straying over alliance territory, warning Moscow sharply and keeping its defences on high alert. Likewise, it has been policingBlack Sea airspace adjacent to nato countries that border the sea—Romania,Bulgaria and Turkey—using a combination of manned aircraft and drones.
These nato actions are having a deterrence effect that is benefiting Ukraine. TheRussians have attacked the Ukrainian Danube ports of Izmail and Reni, but not with the massive firepower that has so damaged Odessa. Likewise, for the commercial vessels operating out of Ukraine’s Danube ports, the presence of nato aircraft over their shipping lanes provides some measure of security from Russian attacks.
One might call this “proximity deterrence”: the closer a Ukrainian facility is to nato territory, the more it will avoid massive Russian missile strikes. The more sea transport lanes there are close to nato shores, the more likely vessels operating there will escape Russian attacks.
How long can this more nuanced notion of deterrence survive? After all, it does have limits: nato is not providing naval escorts for shipping, and Russia andUkraine are engaged in a strike-counterstrike dynamic that changes day by day.As Russia has struck hard at Ukraine’s Black Sea ports, Ukraine has responded by going after Russian ports and ships. It attacked the port of Novorossiysk on August 4th, severely damaging a naval vessel. It has also targeted Russian shipping, attacking a tanker near the Kerch Bridge, which links Russia to Crimea, and which Ukraine also damaged in July.
These attacks delivered a clear message to Mr Putin: we are now able and willing to strike back. The Ukrainians are skilled missileers and they are making the most of their indigenous and rapidly evolving capabilities.
The fast-moving nature of this strike-counterstrike dynamic makes it impossible to predict the future. Indeed, on August 13th a Russian naval vessel fired warning shots at a cargo ship headed for Izmail and boarded it for inspection. The Ukrainian government responded by advising ships to sail as close as possible to the north-western coast of the Black Sea, through the territorial waters of Turkey, Bulgaria and Romania.
As the dynamic continues to evolve, and potentially to spiral, nato must take pains to bolster proximity deterrence, keeping up its air-policing of Black Sea transit lanes close to nato states. It must post constant reminders of the nato promise to defend every inch of the alliance’s territory, including Romanian territory across the Danube from Ukrainian ports. Furthermore, nato should reinforce the message that it tolerates Ukrainian attacks on Russian targets so long as nato-supplied weapons and equipment are not used.
In this way, the alliance can continue to provide the benefits of proximity deterrence—with their inherent limits—to Ukraine’s Danube ports and to shipping in and out of the Black Sea. However, were Russia to increase the pressure in that neighbourhood, nato would face growing danger of attacks straying onto its territory. That could be the moment at which nato-Russia deterrence fails, leading to direct confrontation. The stakes could hardly be higher. Escalation, particularly nuclear escalation, must be avoided at all costs.