His Krugman-ness in the NYT:
Mark Thoma sends us to the new Journal of Economic Perspectives paper(pdf) on optimal taxes by Peter Diamond and Emmanuel Saez. It’s a tough read (I’m still working on it myself), but there’s one discussion that I think helps make a useful point about current political debate.Useful to whom?
In the first part of the paper, D&S analyze the optimal tax rate on top earners. And they argue that this should be the rate that maximizes the revenue collected from these top earners — full stop. Why? Because if you’re trying to maximize any sort of aggregate welfare measure, it’s clear that a marginal dollar of income makes very little difference to the welfare of the wealthy, as compared with the difference it makes to the welfare of the poor and middle class. So to a first approximation policy should soak the rich for the maximum amount — not out of envy or a desire to punish, but simply to raise as much money as possible for other purposes.I was going to say "optimal for whom?" but Paulie K. kindly spells it out: the "optimal tax rate" is the optimal tax rate for the government. It maximizes the revenue of the state, and it's ability to engage in "other purposes." That phrase, however, is not so clear: what are these "other purposes"? How well are they performed? How well is that performance even measured? If the people decide that the government no longer needs to perform them, can they get their money back?