Russia perceives the West as a threat in two ways. First, as a territorial and military challenge. She has repeatedly been invaded from that side over the past 300 years: by Sweden, France, Poland and Germany. This has led her to think of her security in terms of buffers and a territorial glacis so extensively as to make her an aggressively annexationist power herself. Throughout the past 400 years, Russia advanced relentlessly westwards, absorbing swathes of the Baltic, Poland, Germany, Romania and other states. This trend was only reversed after 1991, and has revived again in recent times. Moreover, unlike the West, which sees the stability and prosperity of her neighbourhood as the key to her security, Russia feels safer the more it can make the areas bordering her unsafe and unstable. This means that the security of Russia can only be achieved, in the Kremlin’s mind, through the insecurity of others, either by taking territory from them or preventing them from settling down. It is a zero-sum game.