Sabrina Tavernisi speaks to Serge Schmemann about how Gorbachev changed the world and how Russia's current leader, Vladimir Putin, is trying to change it back. The last time I saw you in person, I think was in Moscow in a New York Times apartment in 2000. Serge was in Kiev during the invasion in February and it really struck him that Putin, in this violent takeover, was essentially trying to put the Soviet Union back together again.