Russia's gas pipeline to Europe did not reopen, as promised, on 3 September. Gazprom said it could close indefinitely. This is no coincidence. Russia's state-controlled gas giant announced the indefinite halt to gas flows through Europe’s key energy artery hours after leading western finance ministers escalated sanctions on Russian oil. Gazprom's official reason is that an oil leak has been found and the pipeline cannot work without German imports of technology, which are now subject to sanctions. Many believe this is an attempt to blackmail Europe over supplies. This is a very serious development. Even during the height of the Cold War, Russia kept supplies of its gas flowing into Europe. However, this cut-off - and the pointed attempt by Gazprom to blame the German energy giant Siemens for the malfunction - is the culmination of decades of dysfunction in the energy relationship between the two countries.