Russian natural gas exports via Soviet-era pipelines running through Ukraine to Europe were halted in the early hours of Wednesday as a transit deal expired. Moscow and Kyiv failed to reach an agreement to continue the flows. Ukraine now faces the loss of some $800 million a year in transit fees from Russia, while Gazprom will lose close to $5 billion in gas sales. We talk to Sergey Sanovich a Hoover Fellow at the Hoover Institution, Stanford University.