Crimea?
I believe it fits. If they had wanted to annex it they would have done so properly. It's not like any other actor would risk all out war over it. If this had been 300 years ago, it would have played out differently. (The status as autonomous region also bring a whole cadre of complications. I don't know much about it really more than you read in history books.)
Please drop this pretense. Nobody invades anything to bring democracy. You can't force democracy on people even if you wanted to. Democracy is so much more than just the elections.
You invade countries because you have geopolitical interests in the area, and want to gain political or economical influence.
It used to be the case that you invaded countries because the territory itself was valuable, but when was the last time you heard invaded people become citizens of the invaders' nation state? These days the cost is calculated and operations carried out are means to an end.