Me vs Mankiw on Global Warming
Two further points with regard to your original blog post:
1. I wasn't making a slippery slope argument. If I had been, I would have argued that carbon taxes would initially be a good thing but would set the precedent for other bad things. In fact I argued that, as implemented, they would probably be a bad thing. As I made explicit in my post, it was a public choice argument—completely ignored in your response. I plan to send in my complaints to the Society for the Protection of Straw Men just as soon as I can find their email address.
2. My argument is consistent with my father's views. For evidence, take a look at the discussion of professional licensing in Capitalism and Freedom. The argument is not that professional licensing, applied by wise and benevolent officials, could do no good. It is that we can expect, on grounds of both theory and evidence, that professional licensing will usually be controlled by the profession and used to restrict entry and raise prices.
If you look again at the quote from him you link to, he isn't saying that one should recommend policies independent of how one thinks they will be implemented—consider the "in light of what can be done." Professional licensing that isn't captured can't be done, or at least not reliably done, on the evidence. He is saying that one shouldn't refrain from making a proposal merely because you think it can't be passed.
In this context, the implication is that one might argue that a specified form of carbon tax would be a good thing and simultaneously that any carbon tax that could be passed would be a bad thing. I don't believe that is your position.
Can you see any hint of evidence that the people proposing cap and trade have made any effort to estimate marginal cost of reduction of carbon dioxide, optimal level of emission, or any of the information necessary for a scheme designed to actually produce net benefits?
Isn't that question relevant to how one can expect a carbon tax (or cap and trade) to be implemented, and isn't that relevant to whether one ought to be in favor of it?