The other mechanism that seems to be on offer is labor supply. This makes a lot of sense to me as applied to low-income people. If you work at McDonald’s or drive a taxi then you face a real choice about whether or not to increase your hours worked at the margin in exchange for more money. Driving a cab at 2AM is obviously a huge pain in the ass and not especially lucrative. To the extent that cab drivers face higher income taxes, they have even more reason not to work so late since it becomes even less lucrative. And the availability or non-availability of late night cabs has a variety of downstream impacts on bars & restaurants, drunk driving, etc.
But it’s a lot harder to see this at the high end. A very large share of high-income professionals basically have a marginal wage of $0. The CEO of WalMart can’t cut back his hours by 5 percent in exchange for a 5 percent pay cut. What’s more, a lot of high-end work is characterized by zero-sum competition. It’s plausible to imagine higher income tax rates making veteran NBA players more likely at the margin to retire rather than play one more season at the minimum. But what are the downstream economic implications of Mike Bibby retiring? There overall quantity of NBA players is fixed and there are plenty of other people willing to step up and do that job. The average quality of NBA talent might decline, but so what? The players just play against each other. And it’s not just athletes. Fancy lawyers and high-frequency traders are playing against each other. Marginal changes in average quality don’t matter. If anything, reducing the average quality of America’s lawyers and finance guys would be beneficial if it inspired more people to do something else with their time.
Last, of course, one of the main reasons for taxing the rich is precisely that the utility of a rich person’s marginal dollar is so low. Giving the dollar to someone else will increase overall well-being.
I think that this is a very strong argument and one that we really need to give more thought to. The empirical data for the effects on growth for taxing high incomes is mixed (at best) and the consequences for accelerating our current recession are non-trivial. After all, we are firing people from government jobs at the same time as there is tepid growth in private sector employment. The stated reason is to try and prevent our budget deficit from growing out of control.
However, if restoring the Clinton-era tax rates did not have a direct mechanism to retard economic growth then perhaps we could fire fewer public sector workers? That would help with the large unemployment rate that we have in the United States and the culture focus of self-worth via paid employment.
I think that the question of higher marginal tax rates on very high income earners does bear some thought.