The country of Crimea, which currently looks to rejoin the Russian Federation, is itself made up of a number of different ethnic and religious groups.
For example, Crimea’s population as of 2013 was roughly below 2,000,000 people. However, this population is not made up of simply “Crimeans,” but rather Ukrainians, Russians, Crimean Tatars, and about 6% that identifies as “Other.” Russians in Crimea are not actually a minority though, as 60% of the Crimean population is Russian. Thus, it should really come as no surprise that Crimea would vote to rejoin Russia, as Ukrainians only make up roughly 25% of the population.
Native Crimeans, which are referred to as Crimean Tatars, are an ethnic minority that were deported by Joseph Stalin in 1944 during World War II. This deportation of 200,000 ethnic Crimeans to Central Asia (Mostly to modern-day Uzbekistan) based entirely on false evidence of collaboration with the Axis has caused the Crimeans to fear another instance of aggression from Moscow.
Since the massive deportation and the collapse of the Soviet Union, many Crimean Tatars have returned, bringing the current Tatar population up to 300,000, who are boycotting the decision by the Crimean Parliament to rejoin Russia.
While Crimea itself does not possess its own military, it relies on the Ukrainian military for protection. There are currently 16,000 Russian troops stationed in Crimea, which has led some to claim that Russia was in fact “invading” Crimea. This is not technically true, as the Russian Federation is allowed to place up to 25,000 troops in Crimea, which leaves up to 9,000 troops that can yet be deployed. Ukraine currently stations troops in Crimea as well, although volunteers are beginning to form “self-defense units” as well as soldiers from the Ukrainian Army.
This multiculturalism is what prevents a clear-cut solution to Crimea, as while the West may see it as Russian encroachment on Ukraine and Crimea, Crimea itself has a troubled history with Russia while the Russians themselves are the ethnic majority. Hopefully this ethnic unrest can be resolved peacefully, and not in another conflict such as the Crimean War.