In Washington policy circles, money and influence can be used to make even the most simple and obvious things complicated and confusing. This is certainly the case with the housing bubble and its aftermath. Four years into the housing bubble downturn, much of the country remains hopelessly confused about what happened, why it happened and who is to blame.

First, what happened is very straightforward. We had a huge run-up in house prices that had no basis in the fundamentals of the housing market. After 100 years in which nationwide house prices just kept even with the overall rate of inflation, house prices began to sharply outpace inflation beginning in the late 90s. By 2002, when some of us first noticed the bubble, house prices had already risen by more than 30 percentage points in excess of inflation. By the peak of the bubble in 2006, the increase in house prices was more than 70 percentage points above the rate of inflation.

This was a huge problem because this bubble was driving the economy. It drove it directly by creating a boom in residential housing construction. We were building housing at a near-record pace in the years 2002-2006. This was in spite of the fact that we had an aging population and record levels of vacancies at the start of the period.

The other way in which the bubble was driving the economy was through its effect on consumption. The bubble created more than $8 trillion in ephemeral wealth in housing. Homeowners thought this wealth was real and spent accordingly. The result was a massive consumption boom that sent the saving rate down to zero in the years from 2004-2006.

When the bubble burst, the building boom went bust. Construction fell to its lowest levels since the 50s as the country waits to gradually work off a glut of housing. Consumption fell back to more normal levels as ...