This is the first of a regular series of columns by our defence correspondent who is in Qatar, the location of the US Central Command Headquarters that will command any invasion of Iraq.
In the military world, size does indeed matter.
It is not so much the numbers of troops or tanks that counts. It is the way units and weapons systems are put together to provide what the military call "combat power".
Despite all the adjectives and hyperbole about the scale of the current US and British deployment in the Gulf, the simple fact is that this is rather a small force with which to contemplate a full-scale invasion of a country the size of Iraq.
Some 250,000 soldiers - half the number assembled for the last Gulf War - have gathered in the region.
This actually provides about 150,000 US and British combat troops.
There is the Third US Infantry Division with about 20,000 men and the 101st Airborne Division with a similar number.
There are around 60,000 US Marines and a British Division of some 26,000 combat troops.
Iraq has an army - albeit of vastly inferior capability - of some 400,000 men.
Missing the war
Even taking this fact into account, US military planners are well short of the five heavy armoured divisions that many pundits believe were essential to mount an invasion at all.
That is why many armchair generals and commentators are expressing concern.
Total: 250,000 soldiers
About 150,000 combat troops
60,000 troops on their way to the Gulf
Over 1,000 warplanes
Some 60,000 additional US troops are on their way to the region.
But these so-called "follow-on forces" will probably miss the war.
Uncertainty still surrounds the US Fourth Infantry Division which was supposed to advance into northern Iraq from Turkey.
Its equipment is reportedly still afloat in the eastern Mediterranean and most of its troops are said to be back in the United States.
It too may not now play any role in the initial battle.
Of course the great force multiplier is air power.
The two coalition partners - three really because the Australians have also deployed a squadron of multi-role fighters - have assembled over 1,000 warplanes in the region.
These are much more capable than a decade ago because of new types of precision-guided munitions.
Quite what will happen if US forces arrive on the outskirts of Baghdad and the regime has not collapsed is far from clear
The same number of aircraft can now attack many more targets.
And, if the Iraqi military offers significant resistance, it will be air power that will be used to alter the balance on the battlefield.
Nonetheless, one of the greatest problems facing US and British commanders is to avoid dissipating their forces as they advance into Iraq.
They need to retain their combat power to confront Iraq's best troops - the Republican Guard - who, it is believed, are deployed outside Baghdad.
Military sources here say that they simply cannot afford to drop off too many individual units to garrison cities or gather up prisoners as they advance on Baghdad.
They simply do not have the men.
This operation then is not without risk.
Quite what will happen if US forces arrive on the outskirts of Baghdad and the regime has not collapsed is far from clear.
Air power is the great force multiplier
The last thing the Pentagon wants is a stalemate at the gates of the city.
This war is a test of the concepts behind the theory of "effects-based warfare".
This is the new "in-phrase" in military circles - the idea that you can achieve military goals by carefully selecting critical groups of targets whose destruction could effectively collapse the regime and disorientate its armed forces, thus avoiding the need to defeat the Iraqi military unit by unit.
This is uncharted territory.
The US planners are putting great store in their capacity for swift movement and the ability of their air power to deliver whatever the commanders on the ground need.
Sceptics caution whether all of the problems in co-ordinating air and ground forces - especially during a rapid advance - have really been resolved.
Welcome to what promises to be a vast military experiment. One that quite apart from its geo-political effects, could have a fundamental impact upon the future shape of the US military, especially the US Army.