Cambridge, Mass.

HOMES are the primary form of wealth for most Americans. Since the housing bubble burst in 2006, the wealth of American homeowners has fallen by some $9 trillion, or nearly 40 percent. In the 12 months ending in June, house values fell by more than $1 trillion, or 8 percent. That sharp fall in wealth means less consumer spending, leading to less business production and fewer jobs.

But for political reasons, both the Obama administration and Republican leaders in Congress have resisted the only real solution: permanently reducing the mortgage debt hanging over America. The resistance is understandable. Voters don’t want their tax dollars used to help some homeowners who could afford to pay their mortgages but choose not to because they can default instead, and simply walk away. And voters don’t want to provide any more help to the banks that made loans that have gone sour.

But failure to act means that further declines in home prices will continue, preventing the rise in consumer spending needed for recovery. As costly as it will be to permanently write down mortgages, it will be even costlier to do nothing and run the risk of another recession.

House prices are falling because millions of homeowners are defaulting on their mortgages, and the sale of their foreclosed properties is driving down the prices of all homes. Nearly 15 million homeowners owe more than their homes are worth; in this group, about half the mortgages exceed the home value by more than 30 percent.