WASHINGTON -- With the U.S. officially having ended combat operations in Iraq Tuesday, U.S. spy officials see the country's inability to form a government as the greatest security threat it faces.

Other major security concerns include continued Iranian efforts to stoke militant attacks in Iraq and al Qaeda's severely degraded, but not extinguished, affiliate in Iraq, according to a senior intelligence official.

"It's important that they get their act together," the official said of Iraqi leaders. Unresolved, the political vacuum could lead to an unraveling of stability and security, he said, though adding that it's unknown when that tipping point might come.

Meanwhile, the Iranians continue to provide militants in Iraq with equipment, training, and refuge and are expected to do so "for some time to come," the official said. They are also providing anti-Western militant and criminal groups with components of roadside bombs, the official added.

"Clearly the Iranians are uneasy with an Iraq next door that's aligned with us," the official said. "There's an incipient level of support that comes primarily from the IRGC," the Iranian Revolutionary Guard Corps.

As Americans leave, it is possible that Iran might try to step up its effort to bolster militants and sow instability, the official said, but it's not certain yet exactly how Iran will respond.

Al Qaeda in Iraq is a concern, but a lesser one for now, the official said, adding that it's only very loosely affiliated with al Qaeda's leadership in Pakistan and primarily comprises Iraqis, not foreign fighters.

While al Qaeda in Iraq posed a grave danger to U.S. troops and Iraqi civilians at its peak in 2006 and 2007, U.S. intelligence officials estimate it is now just 10% of the size it was then, the official said, declining to provide totals. Since March, 10 of its top 18 leaders have been "neutralized," the senior intelligence official said.

Al Qaeda in Iraq isn't currently in a position to threaten the stability of Iraq's government, in part, because "it doesn't appear to have a large base of support," the senior intelligence official said.

Yet it maintains the ability to carry out high-profile attacks, currently concentrated in the Baghdad and Mosul areas, and those will probably never be completely eliminated, the official said. Such attacks "could erode security if the government becomes complacent," he added.

With the drawdown in troops, the U.S. will also lose "eyes and ears" on the ground because military units have provided considerable local intelligence, as have the officers assigned to units from spy agencies like the National Security Agency and the National Geospatial Intelligence Agency.

That loss will pose major intelligence challenges, said the official, who declined to say how many officers from the spy agencies will be moved out of Iraq. Until this year, Baghdad, for example, was the Central Intelligence Agency's largest station, and it's now been eclipsed this year by Afghanistan.

While it is difficult to translate intelligence lessons from Iraq to Afghanistan because the countries' governments are so different, the official said, there is at least lesson that applies: "It's indirectly a lesson for staying the course."

By Siobhan Gorman
www.wsj.com