I haven't read the whole book, just fragments m, but I've watch interviews with the guy, and I think what he's talking about is defending a nation's wealth by putting it onto the Bitcoin network. But I think he means "nation" as in the aggregate of the citizens and institutions, not merely the State.
Discussion
I could see some merit to that idea
Yes, it makes sense because in a war, enemies attack each other's national wealth, not just the State's. So defense acts the same way. Ever since the Westphalian system was put in place in the 17th century, the organization in charge of war and defense has been the State, and increasingly so since 1914. But with something like Bitcoin, perhaps we can take that immense power back and give it back to the actual Nation, to a certain degree.