I didn't notice this reddit link go by last month, since I don't check my referrers as often as I used to (heh), linking to my post about teaching things other than trig.
All in all, I feel like I fared well for a site like Reddit, but there was one repeated theme in the comments I wanted to address: The idea that economics would be impossible to teach in high school. The argument was that economics is hard in the sense that true understanding requires advanced math, that economics is controversial in the sense that there is no one accepted theory of economics, and that having a partial understanding of economics could even be worse than no understanding at all in some cases.
All of these things are true. However... for what thing that we teach in high school are these objections not applicable to? The only exception is that arguably you don't need math for some subjects, but every other clause holds across every subject that doesn't solely consist of learning the names of things.
Even if children were perfectly logical machines that could be successfully taught by starting at "the beginning" and brought up in a strictly-proceeding progression of knowledge starting on that foundation, an educational theory that could charitably be described as "disconnected from reality", there's just too much "foundation" to learn. The most foundational discipline I can think of is number theory, and we're not going to be teaching that to five-year-olds any time soon. We have to start by teaching consensus-based approximations of complicated theories, or we'll never have anything to actually teach.
I am quite confident that a high-school curriculum for game theory and economics could be produced that would both satisfy my desires and fit right into to all the other over-simplified explanations of vastly complicated topics that the student lacks the tools or experience to truly appreciate that we are pleased to call the "curriculum" today.