Pentagon officials continue to face criticism that they underestimated the number of forces they would need for the Iraq operation, and the strength of the opposition they were going to face.
In public, they are sticking to the refrain that the plan is good, it is on track, and there have been no delays.
But there is little escaping the fact that they have had to make adjustments because of the potential threat to their supply lines, the strength of opposition around the population centres in the south in particular, and the weather.
Defence Secretary Donald Rumsfeld has been particularly under the spotlight. Critics of the war strategy blame him for pressing the military to move more quickly with fewer forces than they would have liked.
US troops are waiting to attack Baghdad
To add to an already complex picture, Mr Rumsfeld has fired verbal warning shots at two of Iraq's neighbours, Syria and Iran.
According to Mr Rumsfeld, the Americans have information that equipment, including night-vision goggles, has been crossing into Iraq from Syria.
In a stark public warning to Damascus, the defence secretary said that such shipments would be a hostile act and that the US Government would hold the Syrian Government accountable.
He would not be drawn on whether he was threatening military action.
Mr Rumsfeld also had another warning for Iran, or at least to several hundred Iranian-backed Iraqi dissidents he said were present in Iraq.
This was complicating US war plans, he said, and they would be considered combatatants if they interfered with US-led forces.
But he sidestepped the question of whether he was threatening military action. And, just right now, the Pentagon appears to have enough on its plate.
Both in public and behind the scenes at the Pentagon, the civilian and military leadership have closed ranks over the war plan, insisting that it was agreed by all the top commanders.
It is unclear when the push towards the Iraqi capital will be renewed
Still, the senior US Army officer on the ground in Iraq, Lt Gen William Wallace, says the US military is facing a different enemy from the one it expected.
The Pentagon, it seems, underestimated the Iraqis' ability to adapt and learn from the lessons of the past decade or so of US military operations, including their previous confrontation in 1991.
Push still on
Despite the problems, America's top commanders say they are sticking to the priority of pressing towards Baghdad, despite the resistance in the south. But it is unclear when the push towards the Iraqi capital will be renewed.
Any hopes that the Iraqi authorities might have crumbled in the face of the Americans' rapid early advance and heavy initial air strikes seem to have evaporated.
The criticism among analysts and retired senior military officers has been that the initial US-led invasion force was too small, and lacks sufficient firepower.
The Pentagon says that there are at least 100,000 extra troops still in the pipeline to be deployed. But the soonest the closest of those forces, the 4th Infantry Division, will be ready to fight will be a number of weeks.
The initial hope must have been that these "follow-on" forces would not be needed at all, or at worst would have to help simply with mopping up and stabilisation operations after a conflict.
It is looking increasingly as if at least some of these reinforcements may now actually have to join the fight.