Political Ecology — You may know about the idea in biology of the evolutionary stable strategy. An implication of the idea is that a mix of strategies can be in a sort of equilibrium, while a single or pure strategy may be unstable.
As an example, imagine that two populations, one of them aggressive (hawks) and one passive (doves). Hawks will always battle their neighbors over any resource. Doves won't fight under any circumstances. A population made up entirely of doves would be unstable; that is, if a mutation caused the introduction of a single hawk, it would have an immediate advantage, and the hawkish behavior would bully the doves out of existence.
But a hawks-only population would also be unstable. A single dove introduced by mutation would have a long-term advantage. That's because the hawks' constantly aggressive behavior leads to frequent injury, while the dove, refusing to fight, escapes that risk.
Through application of game theory, Smith showed that there is a particular ratio of hawks to doves that forms what he called an “evolutionary stable strategy” for the species. Thus, selection actually works to maintain a balance of different characteristics in the population.
I've always felt a pang of skepticism when strongly ideological people say “If only everyone was [a subscriber to the speaker's ideology], then the world would be just great!” Maybe my suspicion is that pure strategies in politics are recipes for trouble. Historically, the healthiest regimes have head a fair degree of ideological plurality. Might there be some optimal distribution of liberals, conservatives, libertarians, and so forth in a population, each stymying the others to just the right degree — a system of ideological checks and balances? The analogy is quite loose, but are there politically stable strategies?
Folks very motivated to legalize heroin are unlikely to be the same folks who are motivated to keep neighborhoods especially suitable for wholesome childrearing, and vice versa. Folks concentrated on lowering the capital gains taxes may not be focused on directly bettering the plight of the poor. Would it be possible to believe that a mixed political stategy is best, yet still remain a devoted ideological purist, quite aware that one merely fills a necessary and useful niche? Or can a purist properly fill her niche ony when she believes that the world is going to fall apart unless all are converted?