Still, the timing stings, with winter breathing down Europe’s neck.

Even the mere hint of a supply squeeze has governments nervous about heating bills and energy security.

Gazprom’s move is a reminder of Russia’s waning-but-still-potent energy influence in Europe. Sure, the continent has spent the last two years diversifying its energy sources—snapping up LNG cargos and tapping alternative pipelines—but Gazprom’s ability to cause a stir is alive and well.