References to political or politics routinely blend two distinct manifestations, the first of which is between group competition among interest groups, the second of which is within-group competition among ideological positions. Mapping onto these different manifestations of the political are two distinct domains of explanation afforded by multilevel selection’s application to politics. Survival and propagation of an individual’s genetic material are affected by the characteristics and cohesiveness of the groups of which they are perforce a part for reasons of security, genetic relatedness, proximity and population density, mutual advantage, and division of labor. Whether violently as in war or nonviolently as in politics, multilevel selection affords a biologically informed lens through which to view between-group competition in a way that explains why groups alternately cleave apart and cohere. In this first domain of explanation, our point is merely that groups based on common descent, religious affiliation, or regional proximity, though they have competed violently, can also compete politically. We speak of these as political lobbies, factions, and interest groups. However, there is a second domain of explanation, which we detail in this eighth chapter. We explain that political ideologies are not just cobbled together but represent something more fundamentally connected in terms of evolutionary logic. First, in abstract and without context, we simply develop this thesis, associating the political right with group-selection and the political left with individual-selection. After providing a summary statement about how different threats to survival and reproduction map onto different ideological poles we provide two more sections—one explaining the selective forces that maintain these ideological poles and the range of differences between them; and others describing how those selective pressures impart change on individual persons and populations.