kimberly marten is a professor of political science at barnard college and a member of the faculty of columbia university. >> why did this happen now? >> it is a confluence of events in both russia, ukraine, and in the west. in russia, it didn't happen a few years ago because russia was in the midst of an economic crisis. they have gotten past that. even though the economy is growing slowly, they feel that the worst is behind them. it is the return of vladimir putin. he took the presidency in 2012. part of his mission is that russia needed a national identity. >> until recently, the president of ukraine -- what does it happened without him being forcibly ousted? >> you are talking about the acute days of the crisis. this is a question that has been on the agenda for a long time. it is critical to the way putin thinks about russia and its role in the world and it is crucial to thinking about how russia exerts itself. what we have seen over the past three weeks is an improvisation. >> i want to come back to that. let's go back to mr. putin remarks yesterday. we played a small clip. what