There's a political process for that, which necessarily includes central government.
Isn't it suspicious that Ukraine's large, aggressive, well-armed neighbor was somehow involved in the referendum, and then sent in the "green men" to enforce the inevitable results?
And what about the native ethnic Tatars? Russia pretends they don't exist.
If you look at surveys conducted even when the region was under Ukraine, you'll see that it's always had a very pro-Russia bias (Eastern Ukraine in general was staunchly opposed to the Euromaiden protests).
However, it's worth mentioning that Eastern Ukraine has also been heavily targeted with Russian propaganda for decades now and it's quite likely that had an impact. I haven't read into it, but I'd be surprised if they didn't also encourage Russians to move to Ukraine to make it more ethnically Russian. This is pretty much in the playbook of every colonizer (e.g. Israel with Palestine, Morocco with SADR, or China with Xinjiang).
Isn't it suspicious that Ukraine's large, aggressive, well-armed neighbor was somehow involved in the referendum, and then sent in the "green men" to enforce the inevitable results?
And what about the native ethnic Tatars? Russia pretends they don't exist.