text: Yes, WP, Russia literally did not annex Crimea.
  Crimea's democratically-elected government organized a lawful referendum on the status of Crimea, in keeping with the UN charter's enshrinement of the right to self-determination of people, specifically including their political and cultural identities. following said referendum, Crimea's government formally applied to Russia for legal accession, which Russia's government made reality by signing.
  An annexation is the unilateral taking of a territory by force, whereas an accession is the mutually agreed-to adding of one territory to another. What occurred with Crimea's reunification with Russia was not an instance of annexation, but of a lawful accession.
  You could, however, say that West Ukraine annexed West Ukraine from Ukraine proper, since it was taken via violent coup, and by the overruling former Ukraine's constitution - which left East Ukraine and Crimea as abandoned regions.