In light of Mitt Romney's recent tax returns, the economic blogosphere has been kicking around the issue of capital taxation. Ryan Chittum at Columbia Journalism Review has an excellent overview of what people have been writing with "The capital gains preference." This is a response to Dylan Matthews and Matt Yglesias, who each present arguments from economists that capital gains taxes should be lower than other taxes, even potentially set at zero percent.
Many economic arguments are about tradeoffs, but the argument for the zero tax rate of savings, also similar to the arguments for a consumption tax, is usually phrased as an argument about fairness. In order to frame the fairness argument, economists bring up a story of two similar individuals with one as a saver and one as a spender. Yglesias has the framework in his post:
You imagine two prosperous but not outrageously so working people living somewhere—two doctors, say, living in nearby small towns. They're both pulling in incomes in the low six figures. One doctor chooses to spend basically 100 percent of his income on expensive non-durables. He goes on annual vacations to expensive cities and eats in a lot of fancy restaurants. The other doctor is much more frugal, not traveling much and eating modestly. Instead, he spends a lot of his money on hiring people to build buildings around town. Those buildings become houses, offices, retail stores, factories, etc. In other words, they're capital. And capital earns a return, so over time the second doctor comes to have a much higher income than the first doctor. [...]
In the world where investment income is taxed like labor income, the first doctor says to the second "man you're a sucker—not only are you deferring enjoyment of the fruits of your labor (boring) but when the money you've saved comes back to you, it gets taxed all over again. Live in the now. And the thinking is that world number one where people with valuable skills take a large share of their labor income and transform it into capital goods is ultimately a richer world...
Taxing savings by having an income tax punishes the Saver Doctor relative to the Spender Doctor. If you just taxed what they consumed, they would be treated equally.
Yglesias leans on the idea that we'll be a richer world without taxing savings, because people will respond to the incentives against savings here. I don't believe the research bears this out. I'm not an expert, but I believe the impact, if any, is small. In their excellent summary book on taxation, Taxing Ourselves (2004, 3rd edition), Joel Slemrod and Jon Bakija conclude that a "large number of studies have attempted to address these problems to some degree, and they generally come to the conclusion that saving is not very responsive to incentives."
But if the efficiency argument is weak evidence, the fairness argument is assumed to make the case, and make it for zero percent taxation. It is unfair to tax the Saver Doctor even a penny more than the Spender Doctor. Scott Sumner gives a similar example at The Economist: "The proper tax rate on capital income is zero [...] To see why this is so, consider twin brothers who each make $100,000 in wage income. Most people would regard these two people as equally well off, even if one freely chose to consume his income now, while the other chose to consume later. But not advocates of the income tax. They insist the more patient twin brother is 'richer' and deserves to be taxed at a higher income tax rate." Gilles Saint-Paul argues in the same forum that fairness requires that we shouldn't "penalise future consumption relative to current consumption."
In Joanathan Gruber's popular undergraduate textbook Public Finance and Public Policy, the two people are actually Homer Simpson and Ned Flanders!
Consider two individuals, Homer and Ned, who are identical except for their preferences for saving. Both live for two periods, earning $100 in the first period and nothing in the second period. Homer is impatient: he wants to consume his entire income in the first period and nothing in the second period. Ned is more patient; he wants to consume in both periods. Initially, they are both subject to an income tax, which taxes all labor earnings and interest income at 50%.The interest rate earned on savings is 10%. [...] In present discounted value (PDV) terms, Homer pays only $50 in taxes across both periods, but Ned pays $51.11. Thus, savers such as Ned are penalized in an income tax regime.This tax treatment of savings is both horizontally inequitable (because Ned is taxed more simply for making a different choice) and inefficient because it may reduce the incentive to save (because savings leads to higher tax payments).
Let's stick with Homer and Ned. Is this fairness argument against the "inequitable" treatment of Ned either impressive or conclusive? I'd argue no. I'm going to rely on arguments from Barbara Fried's excellent "Fairness and the Consumption Tax" for the following to identify some problems, and I'd recommend her essay if you are interested in learning more.
The first issue is the assumption that Homer and Ned should pay in accordance with their consumption, or that equal spenders should have equal tax burdens, or, technically, that the present value of their tax burdens should be identical. This presupposes what is up for debate, which is what the appropriate tax base is. If the tax base is explicit wealth, then income from savings should also be taxed. There are significant advantages to owning wealth, including security, peace of mind, power, the ability to direct private investment, political control, and much more. It isn't clear why these shouldn't be part of the tax base.