Political Individualism and Psychological Egoism

Modern Political Individualism typically presupposes some Egoistic conatus, Self-Preservation and Self-Interest being the most prominent ones.  Now, one problem with such Psychological principles is that the multiplicity of experiences that they generate lacks any unification, and, hence, they are inadequate to a concept of Individual.  A second is, as has been previously discussed, the difficulty in deriving from them trans-personal Psychological phenomena, such as Sympathy, the reproductive drive, and Genius.  So, Political Individualism is as tenuous as is its Psychological presuppositions.