Of all the problems that the U.S. troop withdrawal won't affect in Iraq, what to do about the number of internally displaced people looms the largest.
As many as 2 million Iraqis — nearly 6 percent of the country's estimated more than 31 million population — are thought to have been forced from the cities and towns where they once lived and are housed in circumstances that feel temporary and makeshift.
More than 500,000 of those are "squatters in slum areas with no assistance or legal right to the properties they occupy," according to Refugees International, a Washington-based advocacy group. Most can't go home: Either their homes have been destroyed or hostile ethnic and sectarian groups now control their neighborhoods.
Those who are displaced internally say the Iraqi government has done little or nothing to help them, and in some cases has even prevented them from returning to their homes.
Iraqi officials concede that the problem is formidable but they challenge the numbers, saying that the issue is getting better.
"Iraq had the first or second or largest number of refugees, inside and outside, of any country in the world; now it is the third or fourth," said Dendar Duski, the minister of migration and displacement in Baghdad. "We are doing our best to solve the security and economic problems that have created this"
Of the more than 250,000 families that were displaced at one time, about half have been able to go home, Duski said.
Those, however, are not the people found in the Qala neighborhood on the eastern edge of Mosul, Iraq's second largest city. Here, thousands of displaced Kurds occupy what used to be a prison complex used by Saddam Hussein's government.
The residents of Qala say Arab militants drove them out of Mosul in a tit-for-tat displacement battle, in which Kurdish and Arab militias targeted members of the other ethnic group, that began after Saddam's government fell in 2003.
Hamid Majeed said the Arab militants who blew up his house in 2007 drove him from the southern Mosul neighborhood of Hay Meethaq. Even though violence in Mosul now is less severe than it was, Majeed said there was no way he'd be willing to go home.
"They bombed our house because we are Kurdish," Majeed said. "At that time, even if you were walking in the street, if they knew you were Kurdish they would shoot you. We had Arabs in the neighborhood who were our friends for 30 years, but then they would tell the terrorists we were Kurds, just for money. It's not safe to live with Arabs."
Majeed said that he and his family, along with many others, remained trapped on the eastern edge of Mosul. Their tribe originally hails from the city of Dohuk, which is well inside the Kurdish-controlled area of Iraq's north, but the Kurdish government stopped Majeed's family from returning there.
"The Kurdish government wants us to stay here because this is part of the Mosul governorate, and in the next election they want more Kurds here so that they will win more seats," Majeed said.
Duski, the minister, confirmed what Majeed said about the Kurdish regional government preventing the return of refugees and that more than 100,000 people were in a similar situation.
"There is nothing we can do for them," Duski said. "The Kurdish government does not want them to return for demographic reasons."
In Hay Meethaq, the neighborhood Majeed fled, one of his former neighbors, who asked to be identified only by the nickname Abu Bassem for security reasons, said it was safe for Kurdish families to return. Graffiti left by Ansar al Sunna, one of the militant groups that destroyed Kurdish houses, was still evident on a wall not far from the rubble of Majeed's house.
One Kurdish family is said to have returned to the neighborhood, but when members were reached on the phone by another man in the neighborhood, they refused to speak with journalists.
Asked whether he might return, Majeed simply said that his neighbors were lying, and repeated that it was no longer safe to live with Arabs.
Others feel that way about Kurds.
The neighborhood of Amin al Ithania in north Baghdad didn't exist until 2005, when families from all over Iraq who'd been pushed out of their homes went there and quickly built cinder-block houses such as the one Umm Sajjad occupies.
Umm Sajjad — a nickname, because she didn't want her real name published for security reasons — first fled Kurdish militiamen in Mosul in 2003. She went to Diyala province, east of Baghdad, only to be driven out of there in 2007 by Sunni Muslim insurgents. She's a Shiite Muslim.
"I don't know who to blame," Umm Sajjad said. "The government, the people? There are many people in our situation. This whole neighborhood is displaced people. We have registered with the ministry, but we receive nothing."
Umm Sajjad's roof won't keep out the winter rains, and she can't afford panes for her windows. She relies on the government food rations that many Iraqis once depended on, but since 2003 the items in the package have been cut, and corruption within the Ministry of Trade has made shortages even more severe.
Saddam's government was notorious for forcing people to move in an effort to change a region's demographics. In the 1980s, he undertook an "Arabization" campaign that sought to place Arab families in Iraq's Kurdish north, which is rich with oil.
Prime Minister Nouri al Maliki's government stands accused of employing similar tactics. In 2008, the U.S. Embassy in Baghdad acknowledged in a secret cable to Washington that Iraqi forces in Abu Ghraib were preventing Sunni families from returning to the area while encouraging Shiite families to come back.
Abu Ghraib is part of the "Baghdad Belt," the demographically mixed cities and villages that ring the capital and have seen some of the worst violence of the last eight years. They've been a major focus for the U.S. military, and they continue to be contested areas.
Now tribal sheikhs from Abu Ghraib say that the Muthanna Brigade, the Iraqi army unit that's controlled the area since 2008, is targeting Sunni families, some of whom have left because of harassment and the danger of arrest. A delegation of sheikhs from Abu Ghraib met with Maliki in October to voice their concerns, but the sheikhs said nothing had changed.
"It is a new operation of displacement," said one sheikh from the area, who also requested anonymity. "What can we do?"
The Ministry of Defense declined to comment or to allow a reporter to travel to Abu Ghraib to speak with the Muthanna Brigade.