If you believe in freedom (and most modern-day people do not), then you believe in freedom of self-determination. That means people should be allowed to decide what kind of government they have or don’t have. It’s what separates us in the Western world from places like North Korea.
This means that if a certain state, province, city, or whatever within your country wants to declare independence and break away from your nation, you should let them.
If Scotland wants to be independant of England, let them.