Barack Obama took over after Vladimir Putin's first aggression, in Georgia. In 2009, he did the reset policy because they had these stupid ideas about former president Dmitry Medvedev. They thought he would be the leader, not Putin. Everyone played this game with Medvedev as their bet, Berlin, Paris, London, the idea of smoothly transferring to something more acceptable. It was always a charade, a Putin project to solidify his power and come back after four years of nominal occupation of the office by Medvedev.
