After months of vows to bring US troops home from Iraq, presidential candidate Barack Obama is struggling to explain his plan in the light of recent security gains.
More than five years after the US invasion, the Iraq war is now enmeshing not only the Bush administration which started it - but both men fighting to inherit it, Democratic White House hopeful Obama and Republican John McCain.
Obama is torn between a vow to end the war - which underpinned his win over Democratic foe Hillary Clinton - and Republican claims his plan invites US humiliation, would delight terrorists and waste gains bought in American blood.
The war remains broadly unpopular, but it has fallen behind the economy as the top campaign issue, following a lull in violence. Last month, more American troops were killed in Afghanistan than Iraq.
Under rising Republican pressure, Obama said he may "refine" his policies after meeting US commanders in Iraq on a trip expected this month but later reaffirmed his earlier position.
"I have seen no information that contradicts the notion that we can bring our troops out safely at a pace of one to two brigades per month," a frustrated Obama said.
"My first day in office, I will bring the Joint Chiefs of Staff in, and I will give them a new mission, and that is to end this war."
Obama says he can get most US combat troops home within 16 months, leaving behind a smaller force to fight terrorism and protect the US embassy.
His reluctance to pull US troops out quickly appears at odds with much of American public opinion, and brackets him with the highly unpopular President George W Bush.
"We have had an administration and we have, in John McCain, a theory of Iraq that we should just indicate that we will stay there indefinitely and one day, perhaps the Iraqis will wake up and decide that they're willing to work through their differences and reconcile," said Susan Rice, a top Obama foreign policy aide.
"Barack Obama's view is that that has not succeeded five years in, and moreover it's unsustainable."
According to the latest CNN/Opinion Research poll, 30 per cent of Americans favour, and 68 per cent now oppose the war.
Sixty-four per cent believe US troop numbers should be cut, compared to 33 per cent who think they should remain the same.
