My wife, a former math major, freely admits that she’s not particularly good at arithmetic. Knowing group theory and being able to calculate a tip quickly are two different skills. Similarly, knowing economic theory and handling your own money competently are two different things. This is illustrated quite well by Greg Mankiw, who uses some really bad assumptions to claim that his effective marginal income tax rate is 90% . . . and of course it’s all Obama’s fault. Now, I might not be a Harvard economist, but even I know about tax-deferred investments and about half a dozen ways to avoid the estate tax – especially on money saved for a child’s education. I know that very few individuals actually pay their top marginal rate, even fewer corporations do, and that a tax rate on earnings is not the same as a tax on dividends and capital gains. Mankiw pretends to know none of these things, so either he’s not smart enough even to find Harvard on a map or he’s deliberately misrepresenting facts to his readers.

Behind the mathematical lies, though, lurks an even worse deceit. What applies to Mankiw doesn’t apply to everyone. He may be able to forego $1000 in income out of petulance at what he sees as a too-high tax rate, but anyone at or below median income would have to consider it more seriously even if the tax rates were as high as he claims. Also, economics might not be a zero-sum game but, at an annual growth rate of only a couple of percent it’s damn close and taxes are even closer than income. We’ve all heard about trickle-down and the “bigger pie for everyone” and so on but, Brad DeLong points out, Mankiw also helped shape policies that do a notably poor job of demonstrating any such effect. DeLong also quotes Friedman as saying, “To tax is to spend.” Somebody has to pay for all of the costs Mankiw helped impose on us. If not the rich, then who? If not now, when? If Mankiw pays less in taxes so that his children can have more money – which they’ll hardly need – for college, who else’s children will have less? Almost certainly someone who has benefited less from our system of tax and property and liability and regulatory law than he has. Maybe someone who pays the taxes Harvard doesn’t, or whose taxes in other years were directed into Mankiw’s pocket while he as an adviser to George W. Bush, or who got screwed by one of the policies he promoted.

Yeah, go take a break, Greg. The fewer hours wealth-destroyers like you work, the better off we’ll all be.

Don’t worry, I won’t make a habit of writing political posts. It’s been a long time since the last one and it will probably be a long time before the next. I just had to get this off my chest, and it’s my blog. I’ll be returning to the technical content shortly.