Lakoff's most important contribution to us is the idea of framing. I find his explanation of "the" conservative and liberal frames, however, somewhat lacking. Not that his conclusions aren't interesting, and at least somewhat accurate, but that they just seem to come out of left field. Without some kind of studies showing that similar regions of the brain are activated in thinking about the family and the nation, I'm inclined to remain highly skeptical of that particular portion of his writings. Fortunately, I think that it is possible to explain the conservative and liberal frames using evolutionary arguments and what sort of environments they are adapted to.
The key is to realizing that frames are traits that are subject to natural selection, just like everything else, and thus it may be possible to figure out key features of a frame if we can figure out under what conditions it evolved. There are two tools available to us in feeling out a frame in this way: identifying the state of mind that activates the frame, and conjecture of the conditions where the frame will produce a beneficial outcome (in the sense of increasing odds of survival).
I'll leave identifying the conditions that activate the frames to researchers since that is a question best answered empirically. Here you'll find good old fashioned conjecture (ie I wouldn't bet my life on what I'm going to say) based on logic and what little I know about humanity's history.
For starters, let's look at conditions in the time before humanity settled down to start farming: pre-pubescent mortality was likely high compared to today, humans were not as dominantly at the top of the food chain as they are now, and resources availability was subject to the vagaries of the local weather. This is, I think, enough information to construct a frame.
The most important is, I think, the first. Given the what humans knew back then, the only solution available to that first problem is the vermin solution - throw as many bodies at it as possible. Because of this, it becomes necessary to optimize the birth rate. This does not mean that women were restricted to nothing but child rearing. What it does mean, though, is that dangerous jobs were reserved for the men. Doing this minimizes the effect of casualties on the birth rate. This, alone, is enough to explain the emergence of Lakoff's model of the conservative family. Simply put, being in the warrior class is a dangerous job. Because armies have historically seized power, this tends to lead to patriarchal societies and families.
The second condition honestly does more to explain the need of warriors in a time before armies existed - whether hunting or defending against predators, fighters were needed.
Though the first condition does much to explain the conservative frame, it is not sufficient. The third condition actually shapes the frame to more accurately explain conservative opposition to social programs. In a world where your survival is literally subject to the vagaries of the weather, anyone who takes resources from you literally increases the peril to your life. Thus, though everyone values property, to conservatives it is especially sacrosanct. And anyone who would take property from you is evil if they are not using it to make you safer in some way.
Given the outline above, it is possible to consider what mental states should activate this frame. Two words can sum up the conditions that shaped this frame: danger and uncertainty. So, negative experiences like fear, stress, etc should all activate this frame. It's worth considering, however, that these may, in fact, be two separate frames. Note, however, that they are intertwined because maximizing the birth rate leads to resources being strained - which leads to stress, war, theft, and other conflicts that would trigger the frame resulting from optimizing the birth rate.
What is it that has changed since then that could account for the emergence of another, liberal, frame? This question is harder to answer. Is it the emergence of trade, reducing the economic uncertainty that was condition three, and at the same time permitting specialization? Is it the emergence of cities, partly as a result of trade, where people must live more close together in greater numbers than in any time in history? The geographic distribution of liberals and conservatives would certainly be consistent with the last. Given that trade and specialization are necessary for cities to emerge, the first two can also be considered conditions for liberalism. The odd thing is that these not just conditions in which people exist, but they are also advantages in and of themselves. Even given this, I am having trouble figuring out what sort of frame this would engender. I suspect that it is simply the frame necessary to get along in an area with more people than you can possibly know personally. This could also explain why suburbia swings between the two - it gives its inhabitants the option of what kind of lifestyle they'll lead.
The ideas I have put forward here are hardly complete. I put them forward because it could give Lakoff's ideas a basis from which they can be derived, and has the possibility for predicting more frames and when they may become politically prominent.
BlackGriffen