This is a good post at Reason.com shared by Gary. The title actually mentions "libertarianism" and evolution, but the post itself is all about classical liberalism which - I gather - is what the Cato Unbound posts are all about (I haven't read them yet).
This is not particularly revolutionary stuff, but it's a good review of some of the defenses of liberalism using evolutionary psychology arguments (despite the controversies associated with that particular field). Human fitness is derived primarily from our ability to associate through language, etc., and our ability to think abstractly, which enables wider circles of association as well as innovation. Human social behavior and abstract thought enables us to maintain trade networks, which allow our species to both allocate and exploit resources much more efficiently than other species. Social orders that foster these traits are largely classical liberal in nature, emphasizing limited hierarchical ordering, decentralization, flexibility, etc.
The post specifically contrasts the illiberalism of Marxism to this classical liberal order. Speaking of evolution, the author quotes Peter Singer saying: "It tells the left that some of them have failed because their goals were really unrealistic. For example, if their goals were to achieve equality and to combine that with a high degree of liberty--to have the state withering away, as Marx said--it's very difficult to see how you're going to be able to achieve that. If you let the state wither away, then humans' natural tendencies to form hierarchies and rank and so on are going to assert themselves. What happened specifically with the form of communism that was attempted in the Soviet Union and Eastern Europe was that people went into it with some vague idea that they could have this sort of society. But they kept needing to strengthen the power of the state rather than allow it to wither away. In that sense, the original idea would just collapse. You simply couldn't achieve it. Human beings are not such that you could expect them to work for the common good in the way that the theory assumed. The failure to understand that human nature is not as plastic as socialists often assume is a substantial part of why some of these schemes have failed."
I've bolded a sentence there that I think gets to one of many reasons why I think a more robust political economy actually needs to be a non-libertarian classical liberalism (unless of course we're thinking in terms of a blander "small government"/Greg Mankiw libertarianism).