But their are other major non-economic differences. Implementation is one, as you point out, but so is political feasibility, and so is susceptibility to political monkeying over time. The approaches start to look radically different in these lenses.

I actually have sympathy for Hansen’s point. I don’t understand your point about implementation at all. To me, the tax seems much easier to implement. Much. You don’t have to create an organized market for some brand new commodity. Having spent the past couple of years working in such a market (The CA wholesale power market) I can assure you that they are wickedly complex, constantly needing adjustment and attention, and susceptible to gaming.

Also, I’m not sure I buy your point that a tax has more price uncertainty than c&t. Sure, congress may have to “tune” tax from time to time, but that kind of uncertainty and volatility is nothing compared to a commodity market.

On the other hand, one of the nice things about a tax is the low likelihood, once congress gets used to the money, that they’ll let it get cut up over time.

Anyway, it’s an interest argument.

Good luck in your new gig!