The right of self-determination is usually interpreted to be by a majoritty vote.  You choose your border, adjusting as necesary to ensure you have a majority, and then maybe you have a referendum.  The rut started in Northern Ireland - the border in 1920, the poll in 1973.  Then came the Balkans, the Caucasus, East Timor and South Sudan, i.e., yet more violence, everywhere.  If various bits of Iraq like Mosul or Kirkuk are to suffer the same fate, or Kashmir, or Taiwan and then Xīnjiāng, or some Moslem/Christian states in Nigeria or similar parts of the CAR or various regions in the DRC - the list goes on and on - God help us!