Ever since the Great Depression, economists have known that demand shortages tend to persist in the wake of severe financial crises like the ones that happened in 1929 and 2008.

Once firms had to pay to pollute, they became incredibly inventive at figuring out cheaper ways to eliminate their SO2 emissions.

The upshot is that to send its children to a school of even average quality, a family must outbid half of other similar families who are pursuing the same goal. And that's become dramatically more expensive because of the growth in median house size, which was in turn caused by higher spending at the top.

Every group spends more when its income grows.

In almost every instance, air and water quality goals were met more cheaply and quickly when we taxed pollution than when we tried to regulate it directly.

Virtually all families in the middle of the earnings distribution aspire to send their children to a school of at least average quality. (We'd think ill of any parent whose aspirations were lower.) The rub is that the best schools tend to be located in more expensive neighborhoods.

A flat tax is roughly the same as a sales tax.