Good point by Stratfor:
I think that however the vote goes, unless the nationalists are surprised by an overwhelming defeat, the genie is out of the bottle, and not merely in Britain. The referendum will re-legitimize questions that have caused much strife throughout the European continent for centuries, including the 31-year war of the 20th century that left 80 million dead.
That 20th century strife required governments eager to exploit the nationalism questions in order to bring conquest and glory to their leaders, of course.
If Putin is able to emerge from the Ukraine crisis in a position to extend his run by posing as the protector of Russians and Slavs everywhere (whether they want that protection, or not) rather than rue the day he decided to attain territorial ambitions, strife we will have. Only the body count will be in question.