Fatwa by Imam Abu Haneefah
Dar-ul-Islam (islamic state) would changed to Dar-ul Kufr (non-Islamic State) if all these three condition were fulfilled:
1. When it is governed by Kuf Laws
2. When the Muslims lose their safety
3. Neighbourhood. And that happens if the state has borders with the Kufr state in a way the latter causes danger to the Muslims and becomes the reason behind the loss of their safety.
more 'definition' to come later.....