As regards the notion that democracy, politics and the paradigm of the state is 'the only sustainable way of running a country' that may be right but it does not look so good from where I am standing. It looks to me like everything nasty that happens to humanity has one state or another's fingerprints all over it.
And the democratic state of the USA is no virtuous paragon (where should I start!)
The 'state' may still be the best way to run a nation because a nation is nothing but a construct of the state. Since I advocate that human society needs no such thing as a state to operate in a 'sustainable' (or better put: an enduringly satisfactory manner) I have no need to consider how best to run a 'country'.
'A country is a region legally identified as a distinct entity in political geography' Wikipedia