WASHINGTON - As America re-engages with Iraq and deepens its involvement in the region's web of sectarian conflicts, the Pentagon has made a practical assessment of the brutal job of stabilizing Baghdad: in the future, US forces may be needed on the front lines.
President Barack Obama has ruled out a combat mission, but military officials and former officials say the reality of a protracted campaign in Iraq and possibly Syria may ultimately require greater use of US troops, including tactical air strike spotters or front-line advisers embedded with Iraq forces.
That raises questions over how far Obama can go in the expanding US military power without appearing to violate promises not to drag America into another ground war and highlights different priorities between the White House and Pentagon at the start of what looks to be a long, unpredictable military campaign in Iraq and Syria.
From a military perspective, officials say it makes sense to at least have the option of deploying small numbers of US military advisers alongside Iraqis on the front, time-to-time, even if that appears to contradict Obama's stated policy.
The White House, meanwhile, is keen to signal to US voters that the president who campaigned on ending the war in Iraq will keep this a sharply limited campaign.
Obama has ordered 1,600 soldiers to Iraq since Islamic State fighters swept into the country in June but is seeking to avoid mission creep as he cobbles together an international coalition to "degrade and destroy" the jihadists who want to form of a caliphate in the heart of the Middle East.
American spotters in Iraq, used sparingly, could help avoid civilian casualties as American air strikes pound militants who increasingly might try to hide among innocent Iraqis. "There's some reports out there that they're already using children and other things to start shielding themselves, because they know that will protect them from air strikes," General Raymond Odierno, chief of staff of the Army, said on Friday.
Odierno says he supports Obama's strategy in Iraq and says properly trained Iraqis can carry out the job. But he also won't rule any options out.
That is a traditional refrain in military circles, one that was made more bluntly by retired General James Mattis, who oversaw American troops in the Middle East until last year. "You just don't take anything off the table, up front, which apparently the administration has tried to do," Mattis told a hearing held by the House Intelligence Committee on Sept. 18.
"We have the most skillful, the fiercest and certainly the most ethical ground forces in the world and I don't think we should reassure the enemy in advance that they'll never face them."
The top US military officer, General Martin Dempsey, ignited the debate this week when he told lawmakers he might recommend sending US troops to accompany Iraqi forces on the front lines of the fight against the hard-line militant group that has taken over much of Iraq and Syria.