Europe is finally stepping up enforcement against Russian sanctions evasion. But its work is just beginning.

Belgian commandos rappelled from French helicopters in a daring night operation on at the start of the month to seize the sanctioned tanker Ethera in the choppy North Sea. French President Emmanuel Macron savoured the success, declaring: “Europeans are determined to cut off the funding sources for Russia’s war of aggression in Ukraine by enforcing sanctions.”

But seizures are not the same as forfeitures. And if past is prologue, Europe’s catch-and-release playbook won’t materially rattle at the Kremlin’s coffers. Ukrainian President Volodymyr Zelenskyy understands this. He called Belgium’s seized vessel a “floating purse” and urged Europe to confiscate the ship’s oil.

Europeans would be wise to listen to Zelenskyy.

The stakes for enforcing EU sanctions are rising along with oil prices. The same weekend that Belgium seized the Ethera, US and Israeli strikes on Iran sent Brent crude up 7% at Monday’s open. Russia’s sovereign wealth fund chief Kirill Dmitriev predicts “$100+ oil per barrel soon.” While that figure is likely inflated, the signal is clear: Moscow expects to profit from Middle East supply disruptions. It will unless Europe adds considerable costs to the business of sanctions evasion.

The way to do that is by confiscating the “shadow fleet” — Russia’s hundreds of aged, sanctioned tankers moving hundreds of millions of dollars of crude every day.

The problem is that Europe’s legal architecture was not designed for the task at hand. When European navies board shadow fleet vessels, they do so because a ship is sailing without a valid flag, which under the UN Convention on the Law of the Sea permits any state to board and inspect. Or maybe because an ageing, sanctioned tanker presents an environmental risk.

Either way, the result is typically nothing short of catch and release. In January, France caught the US and EU-sanctioned tanker Grinch to rights for flying under a false flag (a common evasion technique). The owner paid a fine of several million euros and the Grinch sailed free with its sanctioned crude on board.

France’s Foreign Minister claimed a victory, stating that “circumventing European sanctions comes at a price.” But the French achievement was more akin to traffic enforcement than law enforcement.

Estonia and Finland have hit similar walls in clamping down on shadow tankers. Europe’s legal constraints are becoming a predictable transaction cost for Putin’s sanctions runners.

Three reforms would change this.

First, EU countries should create an explicit forfeiture authority for sanctioned vessels and their illicit cargo. They could model the approach of coastal states, which seize and permanently forfeit vessels that violate fisheries law in their waters. If Europeans can grab trawlers, they should be able to target the tankers that threaten their freedom. Proceeds from scrapping the ships and selling their crude could support Ukrainian reconstruction.

Second, EU countries should be empowered to permanently ban crew members found serving aboard a sanctioned vessel from entering European ports and territory. Shadow fleet operators depend on rotating pools of third-country seafarers. Making service aboard a designated vessel a career-ending decision would raise costs across hundreds of ships faster and more cheaply than any boarding operation.

Third, the EU should aggressively enforce existing requirements for vessels transiting EU waters to provide proof of internationally recognised insurance. Past efforts by Baltic coastal states and the United Kingdom have proven unsuccessful, suggesting a greater patrol presence will be needed to enforce new regulations that require proof of vessel insurance.

Europe’s catch-and-release approach to Russia’s shadow fleet must end. Doing so would deal a major blow to the Kremlin’s war effort. Sanctions evaders have learned to flout Europe’s conventional approaches to enforcement, and Moscow knows what it’s doing. If Europe is going to win the evolving sanctions war, it’s best to target the shadow vessels, their cargo, and the crews.

Max Meizlish is a research fellow at the Foundation for Defense of Democracies (FDD). Peter Doran is a senior adjunct fellow at FDD.