Whatever the rights and wrongs of their territorial claim, Russia was never going to accept losing control of the Crimea. They fought the Ottomans, the Turks, the French and the British for control of that peninsula; Sevastapol is their only western deep water port that doesn't freeze up in winter. It's population has always been predominantly Russian, and it was only in the hands of the newly independent Ukraine because of an administrative decision taken during the Soviet era.
Understand that and you get a different perspective on what you call annexation and occupation. Russia's old Tsarist empire is breaking up, her European power and influence are declining. From a Moscovite perspective, the Eastern European threat is not from Russia, it's to her.
