After billions of dollars and nearly nine years of training, American troops are leaving behind an Iraqi security force arguably capable of providing internal security but unprepared to defend the nation against foreign threats at a time of rising tensions throughout the Middle East.
Building up an Iraqi military and police able to protect the country became a key goal of the United States and its allies after they defeated and then disbanded the Saddam Hussein-era force in 2003. As America's role in Iraq fades, the results appear at best incomplete.
Iraqi forces - currently about 700,000 strong - have been largely responsible for security in Baghdad and other cities since 2009, carrying out their own raids and other combat operations against insurgents.
More than 10,000 Iraqi soldiers and police have been killed since the new force was established - more than double the number of American military deaths. Few if any military forces in the Arab world have as much combat experience within the ranks.
"They can kick a door in and knock out a network's leadership as good as anybody I've seen," said U.S. Lt. Gen. Robert Caslen, commander of the NATO training mission, which will soon be disbanded. "I would say that they have the discipline and the tenacity to fight as well as anybody I've ever seen."
Nevertheless, Iraqi forces have their work cut out for them. They will be operating in a country which, although quieter than a few years ago, saw more people killed, wounded and kidnapped last year than in Afghanistan, according to U.S. figures.
The departure of American forces this month also leaves Iraq vulnerable to threats from its neighbors - Iran to the east, Turkey to the north and Syria to the west. A major Arab country of about 30 million people with some of the world's largest proven petroleum reserves is incapable of defending its borders in one of the most unstable parts of the world.
The Iraqi military chief of staff, Lt. Gen. Babaker Zebari, has said it would take until at least 2020 for Iraq to defend its airspace. Without a well-trained and equipped air force, Iraqi ground forces would be hard-pressed to defend against incursions across borders with few natural barriers and little cover from vegetation.
"An army without an air force is exposed," Zebari was quoted as saying in a report last October by the U.S. agency responsible for overseeing Iraqi reconstruction.
Even though a full-scale ground invasion from its neighbors may seem remote, the possibility of incursions from Turkey against Kurdish rebels, or Iranians along disputed border stretches or even from a Syria facing an internal revolt cannot be ruled out, especially at a time when the Arab Spring and the looming showdown between the West and Iran are raising tensions throughout the region.
External defense seemed a low priority in the early years of the Iraq war, when tens of thousands of American troops, tanks, planes and artillery served as a deterrent.
During those years, the main threat was posed by Shiite and Sunni extremists, including al-Qaida in Iraq, who were battling the Americans and their allies in the streets of Baghdad and other major cities. Iraqi forces were organized and trained primarily to augment the U.S.-led force, using the American military as a rough model.
Soon, Iraqi commanders were giving power-point briefings, and their generals were handing out specially made coins emblazoned with their names and units as souvenirs. Iraqi soldiers at street checkpoints were wearing kneepads slouched down around their ankles, again just like their American counterparts.
But there wasn't enough time to develop the full package - logistics, intelligence, medical services and a fully integrated command structure - for the Iraqis to operate as effectively without U.S. support. A budget crisis in 2009 and a lengthy political stalemate the following year "crippled both the qualitative development of Iraq's forces and its ability to implement its own development plan," wrote analyst Anthony Cordesman of the Center for Strategic and International Studies.
The head of Iraqi military intelligence, Hatem al-Magsousi, said it takes the Iraqis a week to plan and carry out a military operation that they could execute in a day with American help.
Such delays could be costly if al-Qaida - as expected - takes advantage of a security vacuum to reconstitute itself following major defeats on the battlefield in the final years of the war.
"Unless the Iraqi security forces continue to put pressure on al-Qaida, they could regenerate capability and come back in an even worse way than they have in the past," said a U.S. military spokesman, Maj. Gen. Jeffrey Buchanan.
Another key concern is keeping the security forces free of any political pressure or sectarian interference. For over a year now, Prime Minister Nouri al-Maliki has effectively controlled the Ministries of Interior and Defense while conflicts between Sunni and Shiite political blocs have delayed the appointments of permanent ministers.
That leaves both key ministries leaderless and without direction at a crucial time.
It also has allowed al-Maliki to pack some units with members of his tribe and appoint political favorites to command positions with no effective checks and balances.
"That means Maliki is making all these senior officer decisions, and that's not a healthy modus operandi for a vibrant democracy," said retired Lt. Gen. James Dubik, who was in charge of training Iraqi forces in 2007 and 2008.
The role of al-Maliki, who spent years abroad as a leader of the Shiite underground resistance to Saddam's Sunni-dominated regime, also threatens to worsen sectarian tensions in the ranks. Those tensions nearly tore the country apart in the dark days of intense communal fighting in 2006 and 2007.
Both the Iraqi Army and police are dominated by Shiites, not surprising in a country where Shiites make up 60 to 65 percent of the population. But Shiite domination still alarms the Sunnis: They remember the years when Interior Ministry paramilitary police, whose ranks included veterans of Iran-based Shiite militias, were accused of some of the most vicious sectarian crimes.
Many people in Sunni-dominated provinces such as Salahuddin and Anbar already complain of Shiite-led forces coming in from outside the province to make arrests without informing local officials.
Public trust is further undermined by corruption, including selling fuel for military vehicles on the black market or pocketing the salaries of nonexistent soldiers.
"The widespread practice of buying command appointments is particularly destructive because it places corrupt officers at the head of divisions, brigades and battalions. Such commanders then commit theft and fraud to recoup their 'investment' in the job," wrote Iraq analyst Michael Knights in a report this summer for The Washington Institute for Near East Policy.
Despite the U.S. military withdrawal, Iraq and the United States will still maintain a security relationship. Gen. Caslen is in charge of a $10 billion weapons sales program that will be run out of the U.S. Embassy next year with nearly 160 military personnel. Hundreds of civilian contractors will train Iraqi troops on equipment they've bought from American companies, including 18 F-16 fighter jets which Baghdad ordered this year.
That will give Washington some leverage with the Iraqis - but hardly to the degree it enjoyed when there were nearly 170,000 U.S. troops on Iraqi soil.
What remains unclear is whether without the Americans, the Iraqi military will continue the transition to a well-oiled professional force, free of political influence and capable of integrating their various weapons systems and units into an effective machine capable of defending the nation.
"Left to their own devices, the transition does not occur," Dubik said.
Lt. Gen. Frank Helmick, deputy commander of U.S. Forces-Iraq, told reporters last week that there is a "question mark right now for external security, but for the internal security we've done all we can do."
"We really don't know what's going to happen," Helmick said.
This program aired on December 14, 2011. The audio for this program is not available.