I would say that cultures interact in much the same way individuals do. In both cases there are things like exchange, mutual cooperation, conflict, argument, persuasion, and coercion.

True. What I would be saying, analogously, is that we have taken the "you-do-you while I-do-me" principle too far: if your friend decides to go out and rape someone, then you have a duty to forceably impose your values on them insofar as they shouldn't be doing that. Similarly, a society has a duty to take over or at least subjugate another society to their values when the latter gets too immoral.

Anti-imperialism is a very limited justification in the first place. But the disorderedness of a society is not in itself a sufficient reason for intervention. Should we intervene in North Korea out of compassion? Perhaps, but perhaps not. Compassion can be a motive, but it is seldom a sufficient condition for action.

Even if the negative consequences were very low (or non-existent), are you saying that the West would not be justified in taking over North Korea by force?

I agree that coercion should be the last resort, but it seems to be a resort; and seems to be a valid resort to stop societal structures that are really immoral; and this entails some version of imperialism, even if it is a much weaker version than the standard ones historically.

What I would be saying, analogously, is that we have taken the "you-do-you while I-do-me" principle too far: if your friend decides to go out and rape someone, then you have a duty to forceably impose your values on them insofar as they shouldn't be doing that. Similarly, a society has a duty to take over or at least subjugate another society to their values when the latter gets too immoral.

...

and [coercion] seems to be a valid resort to stop societal structures that are really immoral; and this entails some version of imperialism — Bob Ross

Well, in virtue of what do we have a duty to prevent immorality? Do we have a duty to perpetrators? Do we have a duty to victims? Do we have a duty to "friends"? Do we have a duty to strangers? Do we have a duty to strangers on the other side of the world?

Even if the negative consequences were very low (or non-existent), are you saying that the West would not be justified in taking over North Korea by force? — Bob Ross

If there were no negative consequences then we would be justified. But even something as simple as resource allocation is a negative consequence, so there will always be negative consequences.

Even if the negative consequences were very low (or non-existent), are you saying that the West would not be justified in taking over North Korea by force?

I agree that coercion should be the last resort, but it seems to be a resort; and seems to be a valid resort to stop societal structures that are really immoral; and this entails some version of imperialism, even if it is a much weaker version than the standard ones historically. — Bob Ross

When both the US and North Korea have nuclear weapons, then the question would this:

How many Americans and what percentage of North Koreans population is a justifiable sacrifice to erase the North Korean dictatorship out of existence? And if with Americans the death toll less than have died of Covid (less than 1,2 million), let's say just Hawaii and the Bay area were destroyed, then how many North Koreans would it be enough to revenge the lost Americans?

Well, in virtue of what do we have a duty to prevent immorality?

Justice—no?

Do we have a duty to perpetrators?

What do you mean?

Do we have a duty to victims?

Yes. To punish the perpetrator and avenge the victim(s).

Do we have a duty to "friends"?

Yes.

Do we have a duty to strangers?

Yes. Do you not believe that you have any duty to be just to strangers?

Do we have a duty to strangers on the other side of the world?

Does being just ultimately depend on where the injustice is happening? Sure, circumstances matter, but, in principle, it doesn’t matter.

If there were no negative consequences then we would be justified. But even something as simple as resource allocation is a negative consequence, so there will always be negative consequences.

Agreed.

We are not justified in going to nuclear war with North Korea, assuming both sides have working nukes, to save the people there. The nation firstly has a duty to its own citizens, and not other citizens of other nations.

Justice—no?

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Yes. To punish the perpetrator and avenge the victim(s). — Bob Ross

Generally we do not believe that everyone has legal standing (locus standi).

Similarly, it is the duty of the judge to punish the perpetrator and avenge the victim, not the common person.

Do we have a duty in justice to right wrongs happening on the other side of the world? I don't know. Maybe, but not really? Not everything is within our jurisdiction. Here is Aquinas:

Again, no man justly punishes another, except one who is subject to his jurisdiction. Therefore it is not lawful for a man to strike another, unless he have some power over the one whom he strikes. And since the child is subject to the power of the parent, and the slave to the power of his master, a parent can lawfully strike his child, and a master his slave that instruction may be enforced by correction. — Aquinas, ST II-II.65.2