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

As the great naturalist Charles Darwin saw clearly, individual and collective interests often coincide, as in the invisible hand narrative. But he also saw that in many other cases, interests at the two levels are squarely in conflict, and that in those cases, individual interests generally trump. That simple observation suggests that market failure is often the result not of insufficient competition (the traditional charge from social critics on the Left), but of the very logic of competition itself.

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.

Prescriptive regulations, such as telling electric utilities what kinds of coal to burn or what kinds of scrubbers to install on their smokestacks, were not only intrusive, they were also grossly inefficient.

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.

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.

There's no indication that middle-income families feel resentful about the bigger mansions and yachts. But the near-rich, whose social circles intersect those of the rich, are subtly influenced by them.