Can you make an argument for believing that?

Using psychological terms in a strictly behavioural fashion for groups/countries seems to me to not just be an analogy but capturing the essence of what is observable. Many of the concepts are similar e.g. identity, cooperation, aggression, lying, betrayal, self-preservation, fear etc.

You can defend this further and claim that even when examining an individual, you will see conflicting identities and traits that resembles the conflict in a group rather than a constant, simple, single identity. The underlying truth appears to not be not that a group does not have psychological behaviours its that a single simple human identity doesn't really exist and is always an emergent property of some collection of heterogeneous smaller parts identities/modes/processes etc.

Then why is it so many other countries don't act as we do? USSR under Joe did; that's hardly a ringing endorsement. Any Scandinavian country would be a good counter argument. Finland has withstood Soviet/Russian intimidation for more than seven decades without running around instigating insane, right-wing police states across the Globe.

> Then why is it so many other countries don't act as we do?

That's simple: they're weak and can't get away with it. The baseline conduct of nation states is basically that of fairly rational psychopaths, capable of evaluating what they can get away with. Deviations from that norm are mostly reminiscent of irrational psychopaths. Anyone who expects "moral", "just" or "trustworthy" behavior from a nation state is just out of their mind.

> Finland has withstood Soviet/Russian intimidation for more than seven decades without running around instigating insane, right-wing police states across the Globe.

Some would say “submitted to” rather than “withstood”; heck, accommodating a powerful neighbor out of fear and inability to effectively resist is called “Finlandization” for a reason.

Finland's foreign policy was benign, but its domestic policies weren't pretty.

Eugenics: http://eugenicsarchive.ca/discover/tree/530b988476f0db569b00...

Kekkonen and the collapse of democracy: http://www.nytimes.com/1973/01/18/archives/finns-extend-pres...

Inability, to a large extent. The relative youth of the US in cultural terms. the simplicity of dealing with a small biddable tyranny rather than a large messy democracy that might not agree with us. The Dictator's Handbook by Bueno de Mesquite & Smith does a good job of breaking down the utilitarian calculus of foreign policy decisions.

Finland did align themselves with Nazi Germany early in WW2 in their effort to counter Soviet actions.

Only after they came to a stalemate and peaceful agreement with the USSR did they split from the Axis and align with the Allies.

Most states lack the means to throw their weight around like the USA does.

Interstate relations are what anarchy looks like.

If you really look at human interactions they are exactly same as nation - level ones: constant fight for individual success with thinly cover of "moral values".

Nations are just groups of people, but I agree with you. I'm not generally in favour of applying terms like sociopathic to large groups.

Saying anything is "just a group" of its constituent parts is misleading and incorrect. Behaviors emerge at system levels that are not present among individual "parts."