Actually, based on R’ Avigdor Miller’s History series (all sourced from the gemoroh and midrashim) the actually running of the country was left up to the sanhedrin – except for the occasional, though severe, interference.
Governments have been known to allow Jews religious freedom throughout the golus, both in E”Y and the diaspora.
My only question was whether the Ramba”n would recognize our E”Y as the one to which such a havtacha applies – this seeming to be the only basis for turning the establishment of the State of Israel into a celebration.