There was no need for rigging the referendum in 2014. The Crimean population was always eager to reconnect with their Russian homeland.
NATO and the European Union have every interest in maintaining a conflictual situation.
Recurrent pro-Kremlin narrative on the illegal annexation of Crimea. No international body recognises the so-called referendum, announced 27th of February and held less than three weeks later.
On March 27th, 2014, the UN General Assembly adopted a resolution in which it stated that the referendum in Crimea was not valid and could not serve as a basis for any change in the status of the peninsula.
Vladimir Putin, the President of Russia, recognised April 17th 2015 that "our soldiers were deployed in Crimea to help the inhabitants express their opinion" (Interfax).
No evidence given to support that "NATO and the European Union have every interest in maintaining a conflictual situation" in Ukraine.