Trying to oppress a group that wants self-determination is stupid. Imagine if the UK government did that to the Scottish vote, I have no doubt that Scotland would've become independent.
On the other hand, not attacking people and instead offering legitimate reasons why staying with the original country is preferable gets better results. Even if a vote is carried out and the results want to secede, it's likely that only a small percentage of the population would even care to vote (obviously the most nationalistic ones who want to secede no matter what), which can easily make the results void in the eyes of most countries.






















