When black fuel oil began washing up on the Bulgarian coast this month and people posted photographs of their stained hands, a large share of the online reaction skipped the investigation and went straight to blaming Ukraine. There is nothing to support that and the source of the oil is still unknown, but the reflex fits a mood that has been hardening for the past year, an anti-Ukrainian sentiment that now reaches for Kyiv first whenever something goes wrong on Bulgarian (and European) soil. I want to set the spill itself aside, because it is the weaker version of a question Europe has already answered several times over with much clearer evidence. My answer is straightforward: even when an incident is technically caused by something Ukrainian, the blame belongs with Russia.

The clearest example happened in Przewodów, a village in eastern Poland. On November 15, 2022, a missile came down on a grain facility there and killed two men. For a few hours the assumption was that Russia had struck NATO soil. Then the investigation pointed the other way: Polish prosecutors and NATO concluded the missile was a Ukrainian S-300, fired by Ukrainian air defense to intercept one of the roughly hundred Russian missiles launched at Ukraine’s power grid that day, and that it had veered off course. The projectile was Ukrainian and the two dead men were Polish, yet the verdict from the people whose job is to assign blame was unambiguous. NATO Secretary General Jens Stoltenberg said the incident was not Ukraine’s fault and that Russia bore ultimate responsibility. US Defense Secretary Lloyd Austin called it another reminder of Russia’s war of choice. The White House put it simply: whatever the forensics showed, the party responsible was the one that had fired a barrage at Ukrainian cities.

That formula has held up every time the situation has repeated and it has repeated often. This spring, a run of Ukrainian long-range drones aimed at the Russian oil terminals of Ust-Luga and Primorsk were thrown off course by Russian electronic jamming and drifted into the Baltic states. One hit a fuel depot at Rēzekne in eastern Latvia on May 7, damaging empty storage tanks and injuring no one. The military damage was close to nothing, but the political damage brought down a government. Latvia’s defense minister resigned, and once his party pulled out of the coalition, Prime Minister Evika Siliņa stepped down within days. Her parting statement is the part worth remembering  -regardless of where the drones came from, she said, the incident was a consequence of Russia’s war against Ukraine. The Warsaw-based Centre for Eastern Studies noted that the Baltic governments deliberately framed these incursions around Russian responsibility rather than Ukrainian error, since Ukraine was acting in self-defense.

The ambiguity is not always there and the contrast matters. In September 2025, around nineteen Russian drones crossed into Polish airspace during a strike on Ukraine and NATO jets shot several of them down, the first time the alliance had fired in this war. Polish Foreign Minister Radosław Sikorski said the scale of it made an accident impossible to imagine and the official assessment was that the drones had been directed deliberately. There was no Ukrainian object to dispute and no forensic puzzle to untangle, and the response was fast and united because of it. The harder cases are the ones where Moscow can outsource the confusion, where a jammed Ukrainian drone or a stray interceptor gives people something to argue about for days and leaves the cause untouched.

None of this lets Ukraine off the hook in the cases where its own drones do go astray. A drone that loses its navigation and locks onto a fuel tank in a NATO country is still a drone that ended up somewhere it never should have been and Kyiv owes its allies every reasonable effort to keep that from happening. When something Ukrainian causes harm in Latvia or Romania, it should be investigated and addressed rather than waved away. Of course, Ukraine has generally offered to help do exactly that.

Proximate cause and ultimate cause are different things, though, and Europe’s own leaders keep saying so. The drone is in Latvia, because it was built to counter Russia’s war and the jamming that sent it astray is a Russian system. The same logic runs through the rest of the spillover, including the refugees who fled west and, yes, the small share among them who commit crimes there (and here), because without Russia’s invasion, none of them would have come.

That brings the oil in Bulgaria back into view, even unresolved. If a sanctioned tanker turns out to have dumped waste off Sinemorets, the connection i obvious. If the culprit is some other vessel, even a Ukrainian one, the Black Sea is still a more dangerous and disordered place because of a war that one government in Moscow chose to begin. Arguing over whose oil washed up is the argument Moscow would prefer we have, because every hour spent on it is an hour not spent on who made it possible.