Consider someone dumb but politically opinionated. What problem are they solving? Tribal affiliation, probably. As a by-product, their political actions are practically directed by the leaders of the tribe.
Now consider someone a bit less dumb who happens to have just enough inspiration to try to solve the problem of what actually works, rather than tribal affiliation. I think it entirely reasonable that this slight increase in inspiration can actually reduce the effectiveness of policies advocated, if the problem is confusing. Sure, the tribe leaders aren't going to make great decisions, because they're solving a problem of inter-tribe politics rather than just what works. But it's entirely possible to do worse, and many people will.
So you're going to see strange signals in the data as people become smart enough to question the ordinary, fail, do better, and find new things to question. At no point are you really sure if smart people are solving the same problem better, or just failing at a new and interesting question. You can work out some good guesses, though I guess this would depend on the nitty-gritty of what the signals look like.
Ah! Indeed, without the distributions - from dumb to smart -, one can't be much certain. However, in many (if not all) cases he doesn't merely calculate what the smart vote is. He analyses and interprets it, and in a very artful way (the guy is smart), although sometimes art is not really necessary, e.g. as in an graph of an increasing monotonical dumb-smart function.
Anyway, you do raise an obvious problem: even if a graph dumb-smart represented something like a monotonic function, how would one know that, after a while, eg. at the 300 IQ point, there isn't going to be a radical change?
I would like to point you guys to the blog FreakoStats, by Garth Zietsman, who according to his profile, "Scored an IQ of 185 on the Mega27 and has a degree in psychology and statistics and 25 years experience in psychometrics and statistics." The main concept discussed there is "The Smart Vote", whose essence, in the author’s words, is as follows:
Many of his posts are based on the choice of relevant, if controversial, topics , and his analysis of the direction and the proportionality of which an opinion on it is related to intelligence, as measured by IQ scores.
An obvious objection would be that smart people would have in many cases common interests, and this could bias the results simply to their interests, in detriment to the interests of the less smart.
Zietsman answers it with the statistical fact that people many times don’t vote selfishly, and that he can (and will) control for some of their interests anyway:
This seems somewhat related to the notorious concept of Coherent Extrapolation Volition (CEV) of humankind. To have a clue of the direction it might take, I believe it is a nice idea to look at the opinion of the smarter (“if we knew more, thought faster, […]”), corrected for selfish interests (“[…]were more the people we wished we were, had grown up farther together[…]”), specially bearing in mind that most results tend to converge (“[…]where our wishes cohere rather than interfere; extrapolated as we wish that extrapolated[…]”).
There are analyses on issues such as Abortion, Free Speech ,Capital Punishment and Corporal Punishments on Children ,Immigration, Gay Rights and many more. The results look good to me personally, and I wouldn't be surprised if they pleased many here too.