Federalist Five - again by John Jay. Once again continuing with this analysis contained in Federalist Four, Jay asserts the diplomatic, military, and economic necessity of union as opposed to distinct confederacies. He starts his analysis of unity vs. disunity by using the example of the British Isles and the separation between the Scottish, English, and Irish that existed before their unification.
Jay asserts that if the states are divided into distinct confederacies, whether it be two, three, or four; it would naturally lead to animosity between the confederacies. As one group grows stronger economically - such as a confederacy of northern states - the others will become jealous and will naturally start to mistrust the stronger group of states. This will lead to division and an easier "conquest" if you will, by foreign nations. Thus, as Jay asserts, it is essential that the States band together to get rid of this possibility for disunity and suspicion.
It is interesting to note, that though Jay's analysis of bordering confederacies and their potential to jealously, rivalry, and war is historically factual; the dangers that he described in this particular passage came to pass regardless of whether or not the Constitution was ratified. Because the Southern States saw themselves as a unique entity, not necessarily tied to the North, they operated their governmental policies for the betterment of their particular region. This can be seen with such historical examples as the Nullification crisis and overall opposition to northern interference in the slavery question.