An in-depth look at the threat of strategic defaults, when financially stable households choose to walk away from their underwater mortgages:

What’s surprising isn’t how many homeowners choose to default strategically, but rather how few do so, given the strong monetary incentives. In many areas, prices have fallen so steeply that the monthly mortgage on a house—if it was acquired just before the housing bubble burst—is twice as expensive as the monthly rent on an identical house. If you were holding such a mortgage, why wouldn’t you default?

The law doesn’t provide much incentive to stay put. It’s true that 39 states permit a lender to come after a borrower’s other assets and income if he defaults. And it’s also true that even in the 11 states that don’t allow that, the restriction applies only to original home loans used to purchase property, not to home-equity lines of credit, while there is some legal uncertainty regarding mortgages issued to refinance existing mortgages. Nevertheless, lenders rarely slap borrowers with a deficiency judgment—a court injunction to pay the difference between the face value of a mortgage and the proceeds that the lender earns by repossessing and selling the house. The procedure is costly and generally not worth the expense because of the limited assets that most Americans own aside from their homes.

With peak-to-valley housing depreciation running between 42- and 47 percent overall, strategic defaults remain a long term threat to the Tampa Bay housing market.

The future cure is pretty simple, if unappetizing: Demand larger down payments from home buyers, a request that's reasonable considering the fall in home prices.

Alas, government-sponsored FHA loans require just 3 1/2 percent of buyers. That generosity would be okay were FHA not dominating the mortgage market.

Government-back loan modifications often deal in amounts well over 100 percent of the value of people's homes. Those are down payments in reverse: The lender/government is paying buyers to take the house. And you wonder why more than half of loan modifications fail after just 9 months.