By Paul Reynolds
World Affairs correspondent BBC News website
Australia is one of 37 nations involved in the Nato operation
The Australian plan to nearly double its forces in Afghanistan, to about 1,000, again illustrates the division between the countries that are willing to fight against the Taleban and those that hold back.
Significantly, the deployment will include many more special forces. The province where the Australians are based, Uruzgan, is expected to be the scene of increased fighting.
Thirty-seven nations take part in the Nato-commanded International Assistance Force for Afghanistan (Isaf), providing more than 35,000 troops between them.
But only a handful are in the front line. They are sent by governments committed to winning against the Taleban and fearful that safe havens will be set up for al-Qaeda again, just as they were before the attacks of 9/11.
The main forces are the Americans (12,000 in Isaf, with another 8,000 under their own national command), the British (going up to 7,700 soon), the Canadians (2,500), the Dutch (2,100), the Poles (who reinforced earlier this year to 1000) and the Australians (going up to 1,000 by 2009).
There are also fighting forces from Denmark, Estonia and Romania. The Estonians are said by one expert to have better armoured vehicles than the British with whom they are based in Helmand province.
The French have some special forces with the Americans.
The main fighting is in the east and south. Elsewhere, Isaf troops are engaged more in peacekeeping and reconstruction than war fighting
The issue of caveats
The division of responsibilities is the result of decisions by national governments to keep their own troops away from major combat.
This has resulted in a list of caveats which prevent their troops from being deployed in certain areas and circumstances.
British General David Richards, commander of Isaf until February, stretched out his arms at a recent seminar in London and said he had had a list of caveats that long.
Nato and Isaf have now worked their way around many of these problems.
Reinforcements from the fighting contributors are being sent to the south and east.
"Caveats have always been an issue and we have worked hard to minimise them," says Mark Laity, until recently the Nato spokesman in Kabul and now chief of strategic communications for Supreme Allied Headquarters in Europe.
"But the problems we had have been lessened by the large number of troops going to the south. All nations in Isaf make contributions to the overall force," he adds.
The caveats are mainly geographical, with governments stating that their forces cannot be transferred out of the areas to which they are assigned.
There are some exceptions for an emergency but the basic position remains.
An example of a smaller caveat is the refusal of some forces (the Germans at one stage did this) to go on night patrols because they lack night vision equipment.
The value of some of the troops in the quieter areas would be minimal in heavy combat, as they are not configured for such fighting.
The caveats of course serve to emphasise the difference between those who fight and those who do not.
The United States increased its combat power significantly earlier this year by adding a combat brigade. Britain announced a reinforcement package in February. The Australians have now followed suit. The Dutch already have Apache helicopters and F-16 fighters.
Canada resumes its role
A major contributor, Canada, has just lost six more soldiers, in a roadside bomb. In Afghanistan, Canada has emerged again in its traditional fighting role, obscured by years in which it sought to become more of a specialist in peacekeeping.
It so happens that this is the 90th anniversary of the allied offensive east of Arras in April 1917, which started well with the Canadian assault on Vimy Ridge.
But other countries, like France, Germany, Italy and Spain, while Nato members and keen to help the Afghan government, do not want to get drawn into fighting the Taleban. The French have carrying out air operations over Afghanistan, however.
In the meantime, longer term plans are being implemented to train and equip the Afghan army and police, on whom ultimate success probably depends.
"We can clear an area with Nato troops," said one Nato official. "But without the Afghan forces there to hold it, the Taleban will filter back."