Attempts to strangle Russian President Vladimir Putin’s war machine with endless sanctions are starting to feel like Europe is shouting into the void.

Each fresh package of measures is met with a shrug by the Kremlin. Meanwhile, Russian tankers slip through European waters, quietly ferrying oil worth billions — the very finances that fuel the conflict sanctions are meant to extinguish: A shadow fleet that operates outside of regulatory frameworks.

Russia’s invasion of Ukraine in February 2022 prompted an unprecedented wave of punitive economic measures from the European Union, Group of Seven and United States. The goal was to cripple the Kremlin’s capacity to wage war by striking at the heart of its economy — oil and gas. These commodities comprise roughly 60% of Russian exports and nearly 40% of state revenue.