The city of Odesa is Ukraine’s economic gateway to the world. Russia does not need to sink every ship entering its ports to blockade Ukraine. It only needs to make the journey too dangerous to attempt.
Since July, renewed attacks on commercial shipping in the Black Sea have done just that, threatening an economic lifeline for Ukraine’s war effort and a major artery of the global food supply. Low water levels in the Danube River and constrained overland routes have left Ukraine with few options.
The city of Odesa is Ukraine’s economic gateway to the world. Russia does not need to sink every ship entering its ports to blockade Ukraine. It only needs to make the journey too dangerous to attempt.
Since July, renewed attacks on commercial shipping in the Black Sea have done just that, threatening an economic lifeline for Ukraine’s war effort and a major artery of the global food supply. Low water levels in the Danube River and constrained overland routes have left Ukraine with few options.
Unless the sea reopens, as much as half of Ukraine’s agricultural exports could be left at risk. The consequences would hit Ukraine’s economy hard and be felt far beyond its borders, driving up global food prices.
There are welcome efforts to fix this. Ukraine and its partners are negotiating ways to restore safe navigation. But Europe shouldn’t bet solely on another agreement with Russia: The first Black Sea deal, signed in July 2022, worked until Moscow walked away a year later. Any new cease-fire could prove equally fragile.
Europe needs a plan that doesn’t depend on Russian cooperation. Physically defending ships is the obvious answer. Yet as U.S. efforts to keep the Strait of Hormuz open have shown, it’s also extraordinarily difficult. In recent weeks, new jet-powered drones have stretched Ukrainian air defenses, terrorizing cities and threatening shipping. The alternative is to make Russia’s commerce raiding more costly.
One option is to turn flags of convenience—the nominal registration of ships in poorer states that need the income and impose few rules—into flags of inconvenience, an idea that we recently explored with the Tony Blair Institute. Ukraine’s partners could allow eligible commercial vessels to enter their registries, subject to national rules. The ships could then swap, for example, Liberian flags for the geopolitically weightier French tricolor or British red ensign.
Europe wouldn’t need to start from scratch. The “coalition of the willing,” led by France and the United Kingdom, has already committed to helping secure Ukraine’s seas following a future cease-fire. It could begin work on the legal and commercial architecture for a coalition merchant fleet now, answering Ukrainian President Volodymyr Zelensky’s call for foreign vessels to get Ukraine’s grain moving.
Flags do not make ships invulnerable. But Western flags could raise the political and economic costs of attacking them. Combined with state-backed war-risk insurance, that could make calling at Ukrainian ports a risk that shipowners are willing to take.
There is already an insurance model to build on. In 2023, the Ukrainian government and insurance broker Marsh McLennan launched the Unity facility, underwritten by insurers at Lloyd’s, to provide war-risk cover for grain shipments. It was expanded to nonmilitary cargo the following year. European governments could explore backing a similar arrangement for participating vessels.
There is also a strong precedent for reflagging. During the Iran-Iraq War, attacks on commercial shipping threatened the flow of oil through the Persian Gulf. In 1987, the United States reflagged 11 Kuwaiti tankers as American vessels. Operation Earnest Will subsequently escorted them through the Gulf and became the largest U.S. naval convoy operation since the Second World War.
The comparison shouldn’t be overstated. In the first convoy under Earnest Will, the reflagged tanker Bridgeton struck an Iranian mine. Later that year, another reflagged tanker was hit by an Iranian missile.
Nor would a Western flag necessarily stop Russia from attacking. Last November, an attack on the Ukrainian port of Izmail struck the Turkish-flagged tanker Orinda. More recently, Bulgaria summoned the Russian ambassador after three drones struck the Maltese-flagged Chelsea 3 in its exclusive economic zone. In a war that is spilling into wider Europe, even a British- or French-flagged ship could find itself in harm’s way without a naval escort.
Yet in some respects, the risk is the point. In the Gulf, putting ships under U.S. jurisdiction gave Washington a direct stake in their security. Giving Europe a direct stake in Black Sea security would likewise make attacks on commercial shipping a matter of European interest. That could help deny Russia a veto over global food security.
A cease-fire in the Black Sea, such as the one being proposed by Turkey and the United Nations, is a good jumping-off point. A lull in the fighting would allow Western-flagged ships to sail without immediately testing the arrangement under fire. It would also raise the stakes for Russia: Breaking a cease-fire to strike a Western-flagged ship is a bigger step than doing so during an ongoing campaign.
There are potential benefits at the negotiating table, too. Western flags in the Black Sea are a win for freedom of navigation. Restoring such freedom could also benefit lawful Russian exports and create space for negotiated compromises, such as halting reciprocal strikes on grain shipments.
But the initiative doesn’t depend on a cease-fire holding or on Russia’s approval. Ultimately, its success would depend on European resolve.
Flag states would have to decide for themselves how to respond to an attack. The choice needn’t be between doing nothing and sending a frigate. Western governments have a menu of diplomatic, economic, and legal tools at their disposal. A Russian attack could trigger additional sanctions or support for Ukraine, forcing Moscow to contend with the consequences.
The key is to decide in advance how attacks will be answered. Some coalition members will be more willing than others. Without credible, agreed commitments, an attack risks triggering a debate on how to respond at precisely the moment that a response is needed. Russia would likely exploit the delay and test whether Europe was really prepared to stand behind its flags.
The wider debate over Russia’s hybrid attacks in Europe offers a useful lesson. In September, NATO Secretary-General Mark Rutte stressed that responses would not always be symmetrical or even public. Moscow would need to know that an attack in the Black Sea would carry costs, without necessarily knowing when or how they would be imposed. Without that, a flag is just a flag.
The price of deterrence is accepting a share of the risk. Ukraine currently carries much of the immediate risk involved in defending Europe. Its partners, while providing enormous resources, have sought to limit their own exposure. As Russia’s gray-zone attacks grow across the continent, Europe should be willing to shoulder more of that risk. It should also be ready to impose dilemmas of its own.
Discussion of Ukraine tends to revolve around divining what Russian President Vladimir Putin might do next. There should be at least as much energy devoted to what Ukraine and its partners can do to change Russia’s calculus. A maritime coalition of Western-flagged ships is a good place to start.