Many decry rising inequality because it makes those who've fallen behind feel impoverished. But it's done much more than cause hurt feelings. It has also raised the real cost to middle-income families of achieving many basic goals. The process begins with the completely unremarkable fact that top earners have been spending at a substantially higher rate than before. They've been building bigger mansions, staging more elaborate weddings and coming-of-age parties for their kids, buying more and better of everything.

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.

It is no exaggeration to say that rising inequality has driven many of the 99 percent into a financial ditch. It also helped spawn the housing bubble that gave us the financial crisis of 2008, the lingering effects of which have forced many OWS protesters to try to launch their careers in by far the most inhospitable labor market we've seen since the Great Depression. Even those recent graduates who manage to find jobs will suffer a lifelong penalty in reduced wages.

If top marginal income tax rates are set too high, they discourage productive economic activity. In the limit, a top marginal income tax rate of 100 percent would mean that taxpayers would gain nothing from working harder or investing more. In contrast, a higher top marginal rate on consumption would actually encourage savings and investment. A top marginal consumption tax rate of 100 percent would simply mean that if a wealthy family spent an extra dollar, it would also owe an additional dollar of tax.

We could curtail private spending by several trillion dollars a year without requiring painful sacrifices from anyone. That would be more than enough to rebuild our crumbling infrastructure and eliminate government indebtedness once and for all.

The link between rational individual behavior and collectively desirable outcomes is extremely tenuous.

For the three decades after WWII, incomes grew at about 3 percent a year for people up and down the income ladder, but since then most income growth has occurred among the top quintile. And among that group, most of the income growth has occurred among the top 5 percent. The pattern repeats itself all the way up. Most of the growth among the top 5 percent has been among the top 1 percent, and most of the growth among that group has been among the top one-tenth of one percent.