> Proof-of-Stake attacks aren't about having 51% of the CPU that overwhelms a Proof-of-Work system, but about having 60-70% of the _value_ in the network.
If a nation buys 2/3 of the coin and destroys the network, investors (as a whole) take a 1/3 loss. Then they can (re)start another PoS coin.
Ironically the nation would be up against the old saying that the market can stay irrational longer than you can remain solvent.