A man must be far gone in Utopian speculations who can seriously doubt that, if these States should either be wholly disunited, or only united in partial confederacies, the subdivisions into which they might be thrown would have frequent and violent contests with each other. To presume a want of motives for such contests as an argument against their existence, would be to forget that men are ambitious, vindictive, and rapacious. To look for a continuation of harmony between a number of independent, unconnected sovereignties in the same neighborhood, would be to disregard the uniform course of human events, and to set at defiance the accumulated experience of ages.

Federalist No. 6