Existing-home sales fell off a cliff in July, hitting a 15-year low as the end of a homebuyer’s tax credit chilled prospective purchasers. Housing stock now has a 12.5 month supply, double the normal number, and with that much housing sitting on the market, prices are sure to fall.

The National Association of Realtors said sales dropped a record 27.2 percent from June to an annual rate of 3.83 million units, the lowest level since May 1995. June’s sales pace was revised down to a 5.26 million-unit pace [...]

One reason the market is hurting is that buyers and sellers are in a standoff over prices. Many sellers are reluctant to lower their prices. And buyers are hesitating because they think home prices haven’t bottomed out.

“It really is a self-fulfilling prophecy,” said Aaron Zapata, a real estate agent in Brea, Calif. “If all buyers perceive that home prices are coming down, then they will stop making offers — and home prices will come down.” The housing market is also being hampered by the weakening economic recovery. Unemployment remains stuck at 9.5 percent and many potential buyers worry they might not have a job to pay the mortgage.

Prices have fallen in part because foreclosures are running about 10 times higher than before the housing bust. Though the average rate for a 30-year fixed mortgage has sunk to 4.42 percent, many people can’t qualify because banks have tightened their lending standards.

Though the median home-sales price rose slightly year-over-year, that statistic is a bit misleading. The indicators clearly show that prices will drop and sellers will be forced to lower their numbers if they want the property off the books.

With the Administration’s foreclosure-prevention program doing little but delaying foreclosures, and more borrowers cycling through the system and going into default, there doesn’t seem to be much of a check on this downward spiral.

In this case, the housing troubles prefigure the overall troubles in the economy. Prices will fall and they need to fall, but the chill in the market is a direct result of high unemployment, increased foreclosures and a general malaise. Without fixing the root cause, housing will never come back, nor will the economy.

It seems preposterous to design systems for funding federal backing of mortgages in this environment. That’s about four or five problems ahead. The economy is in crisis.