Few leaders have had as profound an effect on their time as Mikhail S. Gorbachev, the last leader of the Soviet Union, who died this week at 91.It was not Mr. Gorbachev’s intention to liquidate the Soviet empire when he came to power in 1985. But after little more than six tumultuous years, he had lifted the Iron Curtain and presided over the dissolution of the Union of Soviet Socialist Republics, ending the Cold War.Guest: Serge Schmemann, a member of The New York Times’s editorial board.Background reading: Adopting principles of glasnost and perestroika, Mr. Gorbachev weighed the legacy of seven decades of Communist rule and set a new course, decisively altering the political climate of the world.With the war in Ukraine, Russia’s current leader, Vladimir V. Putin, is trying to unravel Mr. Gorbachev’s legacy.For more information on today’s episode, visit nytimes.com/thedaily. Transcripts of each episode will be made available by the next workday.