The private sector is first of all much larger than the public sector. The waste we see in that sector does not result from the fact that people spend their money carelessly. Mostly, it occurs because what one family must spend to achieve its goals often depends heavily on what other families spend.

Unless we can act collectively, there would be no way to defend ourselves, no way to define or enforce property rights. We couldn't curb congestion or pollution or build and maintain public infrastructure.

As John Maynard Keynes taught us in the 1930s, in such situations, government is the only entity with both the motive and the ability to boost total spending by enough to put people back to work. As it happens there are long lists of important public projects that cry out to be done.

The primary source of waste in government is that legislators are often under heavy pressure to vote for projects that will benefit their campaign contributors, even when those projects fail a simple cost-benefit test. But with the Supreme Court showing little interest in permitting tighter rules on campaign contributions in recent years, there is little reason to be optimistic that we'll start curbing this kind of waste any time soon.

One reason that might motivate a worker to accept a riskier job at higher pay, for example, would be that doing so would enable him to bid more effectively for a house in a better school district. But if other workers did likewise, none would achieve the goal they were striving for.

The fact that many private expenditures are mutually offsetting actually happens to constitute a remarkably good bit of fiscal news. Mutually offsetting spending patterns are wasteful in the same way that military arms races are. In such situations, if each party spends less, nothing is sacrificed, yet resources are freed up that can be put to much better uses.

As economists have long noted, the puzzle is not that so few people vote, it's that so many do. After all, no individual's vote has ever tipped the balance in a presidential election.