That's not how nation-states work. The US would spy even if no one else spied, just like the US invades other countries despite no serious risk of being invaded and overthrown itself. (Such an invasion would be suicidal; the invader's nation would be vaporized within minutes.)
We could go on: the US incarcerates its populace far more than other nations, even though its populace isn't more genetically predisposed to criminality.
Nation-states are artificial institutions which make war and control their subjects. They're remarkably similar to the mafia model. "Defending its populace" is akin to a protection racket. (For example, the US's actions clearly have the effect of increasing risks, not reducing them.) Dispute resolution (courts, etc) and top-down "democratic" forms are the result of needing to demonstrate some legitimacy lest they be overthrown by their subjects. Even in a rich country like the US, most people still have little ability to participate meaningfully in the legal/political/economic systems; and in presidential elections, very few votes actually count (due to the electoral system).
Since the US is the most powerful nation-state, it's the most violent; that's a correlation that runs through history. In particular, its capacity for violence (military) has no competitors. (It also has the most advanced economy, but it's no longer so advanced in this dimension as it was after WWII.)
I never claimed wouldn't spy is no one else spied. Of course they would. Of course the US isn't concerned with invasion, it's concerned with having an influence, and having democratic or at lest US-friendly trading partners. Just like the USSR had their interests.
What do you think would be a good alternative to nation states? For instance, I think using the US electoral system is a bad example of how people can particilate in their government, so I think it's a bad example if you try to discredit the idea of nations.
This is not to say that the U.S. has always acted in a way that reduces the risk of war. And obviously there's nothing positive to say about the 2003 invasion of Iraq. But the military itself does not inevitably lead to massive violence. Even in Iraq most of the casualties have come from Muslims killing Muslims.
We could go on: the US incarcerates its populace far more than other nations, even though its populace isn't more genetically predisposed to criminality.
Nation-states are artificial institutions which make war and control their subjects. They're remarkably similar to the mafia model. "Defending its populace" is akin to a protection racket. (For example, the US's actions clearly have the effect of increasing risks, not reducing them.) Dispute resolution (courts, etc) and top-down "democratic" forms are the result of needing to demonstrate some legitimacy lest they be overthrown by their subjects. Even in a rich country like the US, most people still have little ability to participate meaningfully in the legal/political/economic systems; and in presidential elections, very few votes actually count (due to the electoral system).
Since the US is the most powerful nation-state, it's the most violent; that's a correlation that runs through history. In particular, its capacity for violence (military) has no competitors. (It also has the most advanced economy, but it's no longer so advanced in this dimension as it was after WWII.)