Today, as the deadline arrives for U.S. troop withdrawal from Iraq's cities, peace and stability seem as distant as ever. Iraq's continuing middle-class refugee disaster is perhaps the central barrier to a durable peace and shows no sign of abatement. This crisis -- the largest human displacement since 1948 -- has been largely ignored for the past six years.

The media's failure to report this massive tragedy is disappointing but perhaps not surprising given the plethora of underreported humanitarian crises in the world today. However, this is not simply a distant humanitarian catastrophe. It has grave and unexamined consequences for the future of Iraq, a shattered nation that desperately needs its native professional class to return and help rebuild the country.

With some estimates of civilian injuries numbering in the millions, the need for health care in Iraq has never been greater. Unfortunately, there are half as many health care professionals in Iraq today as there were in 2000. Iraq still lacks basic electricity, water and sanitation services. This is startling when one considers the hundreds of billions of dollars U.S. taxpayers have poured into rebuilding Iraq. The stark and unacknowledged reality is that the refugee disaster has made rebuilding Iraq impossible at any cost; there are simply not enough professionals left there with the technical skills and desire necessary to rebuild their homeland.

Forty percent of Iraq's middle class now rents apartments in neighboring Jordan and Syria. These refugees live off their dwindling life savings and whatever assistance they can scrape together from relatives, friends, charity organizations and under-the-table employment. Like undocumented workers in the United States, their professional certifications are invalid, and they cannot legally work. Doctors, lawyers and engineers have turned to street vending, day labor and prostitution.

The United Nations estimates that 4.7 million Iraqis -- nearly 20 percent of the prewar population -- have been displaced. Despite relative calm in recent months, less than 7 percent of the displaced have returned to their communities. The United States is in the process of leaving Iraq. Why isn't Iraq's middle class returning home?

Aside from the still-dangerous security situation, many do not have homes to return to. Years of ethnic cleansing have homogenized once-diverse Iraqi neighborhoods. Millions of displaced Iraqis have discovered that squatters, many of whom are displaced themselves, now occupy their homes. Unresolved property disputes are one of the main reasons displaced Iraqis are not returning home, yet neither the United States nor the Iraqi government has shown any willingness to adjudicate these disputes.

Taking advantage of the lull in violence caused by successful ethnic cleansing, the United States has spent the past two years sealing off entire neighborhoods in Baghdad with miles of concrete barriers, effectively endorsing the newly homogenized reality and making movement around Baghdad extremely difficult. While this may have been an effective short-term tactic to quell sectarian violence, Baghdad's walls carry the long-term risk of discouraging Iraq's middle class from returning.

The Iraqi government, understanding the importance of the displaced middle class to rebuilding efforts, has offered $800 per family and free airfare to refugees who decide to return. The problem is that Iraq is not yet able to reabsorb the refugee population; citing continued security concerns, the United Nations is not recommending a large-scale return. Consequently, many of the relatively small number of Iraqis who have returned from neighboring countries are now internally displaced inside Iraq. The Iraqi government is attempting to put the cart before the horse, so to speak, by making returns a component of its security strategy rather than a consequence.

As today's deadline arrives and recedes into history, it's worth acknowledging for the first time the Catch-22 at the center of Iraq's problems: Those in the displaced middle class hold the key to a stable country, yet they fear returning to the unsafe, unfamiliar and ethnically homogenized hell that Iraq has become. The solution is far from obvious, but the first step toward solving any problem is understanding its dimensions and, indeed, that a problem exists.

Nathan Fisher, of St. Louis Park, is the director of "The Unreturned," an upcoming documentary film about Iraq's middle-class refugee crisis.