Demographics of Crimea point of time. Turkey has provided the greatest support to Ukraine, which has been unable to resolve the problem of education in the mother tongue in Crimea, by bringing the schools to a modern state. Ukrainian was until 2014 the single official state language countrywide, but in Crimea government business was carried out mainly in Russian. Attempts to expand the usage of Ukrainian in education and government affairs have been less successful in Crimea than in other areas of the nation. Currently two thirds of migrants into Crimea are from other regions of Ukraine; every fifth migrant is from elsewhere
Annexation of Crimea by the Russian Federation also signed the Budapest Memorandum on Security Assurances, by which all these countries reaffirmed their obligation to respect the territorial integrity of Ukraine (including Crimea) and to refrain from the threat or use of force against the territorial integrity or political independence of Ukraine. According to the Constitution of Russia, the admission of new federal subjects is governed by federal constitutional law (art. 65.2). Such a law was adopted in 2001, and it postulates that admission of a foreign state or its part into Russia shall be based on a mutual accord between the Russian Federation and the relevant state