The relationship between NATO and Russia is in deep crisis. Vladimir Putin's threat to use nuclear weapons on the Ukraine battlefield is taken very seriously by the Alliance, which has condemned Russia’s irresponsible nuclear rhetoric and coercive nuclear signaling. In fact, the once cordial partnership between the North Atlantic Treaty Organization and the Russian Federation is at its lowest since the dark days of the Cold War. NATO leaders believe Russia poses a direct threat to the Alliance, but their collective condemnation is falling on deaf ears in Moscow.
So, how has a previously constructive relationship between NATO and Russia turned so fractious? Click through this gallery and find out more about why Russia fell out with NATO.