Preventing foreclosures has become a top priority of politicians, economists and regulators. In fact, allowing foreclosures to happen has merit as a free-market solution to the crisis.

If the intent is to help homeowners, then foreclosure is undoubtedly the best solution. Household balance sheets have been destroyed by taking on too much debt via the purchase of inflated assets. With so little savings, a household with negative equity almost implies negative net worth. Walking away from the mortgage immediately repairs the balance sheet.

Credit may be damaged, but homeowners can rebuild it. And by renting something they can afford, instead of the McMansion they cannot, homeowners are most likely to have some money left over each month that they can save toward a down payment on a house they can eventually afford.

If the intent is to help the credit markets, then foreclosure is undoubtedly the best solution. The securitization model has proven to be flawed. Slicing loans horizontally into tranches created asset classes that have conflicting interests in a dissolution strategy of the same underlying asset. The holder of a senior tranche would be agreeable to modification, since his position is secured; the holder of a junior tranche would essentially be wiped out. The lower tranches are worthless but are still legally an encumbrance, hindering any type of sale or work-out effort.

Consider a property that sold for $500,000 at the peak, financed with a $400,000 first lien and an $80,000 second lien, which is now worth $300,000. The second lien is worthless, but the lien will remain as a cloud which complicates any modification effort by the senior lien holder. There is no incentive for the junior lien holder to voluntarily agree to a modification. Foreclosure would be the best and finite action. It wipes the slate clean.