However events unfold at the United Nations, there's been a real sense at the Pentagon of a change of gear and a change of atmosphere in the last few days, at least along the hallways where the war planners and operations staff have their offices.
President Bush may not have made a decision on military action yet, but the feeling in the Pentagon is that the US military must be ready to respond at any moment.
Air sorties have increased ten-fold in six months
Another sign that the tempo of preparations really has increased is that the number of air patrols in the southern no-fly zone over Iraq has gone up dramatically.
Something like 800 sorties a day are being flown. That's getting on for ten times the level of about six months ago.
There are a number of motives for doing this. First, it familiarises new aircrew with the terrain. It also gets them used to flying with large numbers of other aircraft in the air.
And perhaps most importantly, with such a high level of activity, it means that it should be more difficult for Iraqi air defences to spot a real attack when it comes, if indeed it does.
The Americans have also been "shaping the battlefield", intensifying air strikes on Iraqi targets - particularly air defences - albeit still, the Americans say, in response to Iraqi "provocations".
'Shock and awe'
The man who would run the war, the head of US Central Command, General Tommy Franks, insists the United States and its allies are ready if President Bush decides to take action.
Military officials say that, if that happens, the US war plan is to "shock and awe" the Iraqis into early defeat with an onslaught of simultaneous or near-simultaneous air and ground attacks that would be very different from the last Gulf War.
US troops are acclimatising to life in the desert
Reports suggest that the first 48 hours would see the launching of some 3,000 precision-guided weapons, ten times the number dropped in the same period in 1991.
The number of cruise missiles launched in the first two days would reportedly be double the number fired in the entire 1991 conflict.
Also unlike in the last Gulf War, ground forces will move rapidly to take over key targets.
Three large gaps have been cut in the electric fence running along the border between Kuwait and Iraq, the UN has reported, possibly to speed the path of any invading ground force.
Defence officials have cautioned against expecting a "linear" front line, that units will focus on specific areas - using fast-moving helicopter-borne forces as well - in a strategy that's been called "vertical envelopment".
Clearly, Pentagon planners hope that large parts of the regular Iraqi army will put up little or no resistance.
The concerns are the Republican Guard and Special Republican Guard forces, particularly those around Baghdad.
WITH TURKISH BACKING
Plan A: Thousands of US ground troops backed by tanks pour into northern Iraq
Objectives: Capture key towns Mosul and Kirkuk. Force would then move south to Tikrit and Baghdad
They expect these forces to try to draw the US military into an urban fight.
One of the other big concerns for the Pentagon is what will happen in the Kurdish north of Iraq.
Turkey's delays in giving the go-ahead for a troop build-up there has denied Washington its preferred option for creating a northern front and getting US forces into the north.
The Pentagon will still want to put forces in there. But without Turkey, they'd have to drive or be flown from Kuwait, or flown from further afield, including even directly from the United States.
The forces that could be deployed quickly would be smaller, while heavier forces would take longer. That complicates and could slow down an already complex war plan that relies on speed.
WITHOUT TURKISH BACKING
Plan B: Airborne force with light armour takes key towns and seizes oil fields . Ground troops cross desert from Kuwait in support 
Objectives: Capture key towns Mosul and Kirkuk. Secure oil fields
But the uncertainty over Turkey will not hold up any decision to take action.
The Pentagon's "Plan B" does not rely on having the forces earmarked for Turkey redeployed elsewhere.
General Franks will simply re-assign the forces he already has available now, and fight with those.
But that's why the Americans say a conflict without ground forces pouring through Turkey will be longer and more difficult.
The Pentagon is clearly still in the final stages of preparations. But, for the moment, the US military is to some extent a bystander as what President Bush calls "the final stages" of diplomacy in the Iraq crisis play out.