Bangladesh, Feb. 26 -- The Druzhba oil pipeline, whose very name evokes the ideal of friendship, is now proving that names can lie. Once a symbol of cross-border energy cooperation, the pipeline is today at the center of a high-stakes geopolitical struggle in which “friendship” seems to have evaporated entirely. Hungary, long dependent on Russian crude oil flowing through the pipeline, is now raising the alarm-and the stakes-over its future energy security. The twist? European Union officials appear remarkably unconcerned, leaving Budapest to consider measures normally reserved for far graver threats, including the deployment of its military to protect what is effectively a vital lifeline.

Critics of Hungarian Prime Minister ...