Well, I can answer your question on why Norway and New Zealand are more stable than Ireland and Israel (by the way, were you trying for consonance, or did it just happen?). Norway is more stable because it has almost no history of divisive internal conflicts, and not much more for external. New Zealand had some conflicts, but for the most part, the invaders, both Maori and European, were so succesful that those of the original populations left didn't do much. In Ireland and Israel, there has been and still is great sectarian strife, resulting from their many invasions and colonizations, ranging from partial success to abject failure.