On the question of "when is it 'wrong' to intervene in the internal affairs of another nation?" one could see what I am saying as might makes right, but I think that misses some subtleties. Take the world as it exists today, with a militarily dominant US. If our western allies band together, it does not take very many of them for cause the US some degree of political discomfort. That discomfort may not be enough to prevent the US from doing what it wants to do (as was the case in Iraq), but it is a real cost imposed on us. So were we "wrong" to invade? I good part of relevant opinion seems to think so, both inside and outside the U.S. So despite the military might, and despite the fact that Iraq was in no position to stop us or put up a credible defense, it is not clear that US military might made us "right" in the face of the objections of our allies. That said, I don't find it especially meaningful to say that reason we may have been wrong to invade Iraq was that we were violating its "sovereignty." The real reason other nations objected was a generalized fear that our future interventions may have more direct negative consequences on those other nations (either they would be invaded or some interest of theirs would otherwise be impaired). It is that fear that is the basis for why nations tend to pefend (in word and action) the so-called "sovereignty" of other nations.