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 most glaring deficiency in traditional economic models is that they completely ignore the role of context in evaluation.

Only the federal government has the power to spend beyond its current revenue. It shouldn't do that when the economy is at full employment. But it's an essential step for an economy mired in recession.

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.

In short both the things we feel we need and the things available for us to buy depend largely—beyond some point, almost entirely—on the things that others choose to buy.

Many social critics wag their fingers at what they perceive to be frivolous luxury spending. But that misses the point that consumption norms are local. It's not just the rich who spend more when they get more money. Everyone else does, too. The mansions of the rich may seem over the top to people in the middle, but the same could be said of middle-class houses as seen by most of the planet's seven billion people.

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.