You do realize this is not an "election" procedure, right? "Election" implies that some group of people is choosing their rulers or representatives. Given that this obviously disenfranchises the vast majority of the population even more than now, I must infer that you don't consider the popular will a factor that should play a major part in government.
Also, even granting that IQ tests are as reliable as you assume, you still need to justify a few things:
- Why do you assume the comparative advantage of these extraordinarily IQ people is to spend time as a representative, rather than in academia, science, business, non-elected positions in government, etc? I'm not convinced that the 0.1% most intelligent people make a particularly better voting body than the top 1%, or for that matter the top 15% percent, which certainly includes the majority of our elected representatives today.
- It's been argued that rationality and intelligence in the sense measured by IQ tests are not particularly closely correlated, so I'm not sure why extreme quickness of thought should be privileged in particular for representative positions. Related to that, there seem to be a large number of high-IQ cranks that I wouldn't want to trust the fate of an entire nation to -- for example, Mencius Moldbug.
- Do you have any particular reason to believe that the high IQ members of this body would vote for the good of the entire nation, rather than in their own interests (granted, you've already privileged them with your proposal to use IQ tests pervasively in society)? 0.1% of the US is 320,000, and though your mechanism might prevent the small number of representatives at a given time from enriching themselves to Third World-dictator standards, I don't see any reason they wouldn't grant all 0.1% highest IQ people a $1m per-annum -- it would only cost $320b/year, less than 10% of the 2016 federal revenue.
This mostly sounds like a technocratic wet dream to me -- you could have Robin Hanson rule the U.S with no opposition at all.