Then if I make a conclusion from your posts, this is what I understand:
1. Nobody is appointed by God today as a leader.
2. It is not possible to prove or disprove if someone truely understands and follows Quran.
Question:
Then, if someone establishes an islamic state today, and claims to have the True Islamic Laws established and enforces laws of Islam on people according to his understanding, Is this allowed in the Quran?
(2) is not True. It's just that we are misinterpreting Islam at the moment. It's not that it's not possible to provide proofs for true interpretation.