Why did the Northern Alliance take Kabul so swiftly?
The Northern Alliance's clean sweep in the north of the country is a product of the military momentum of their offensive backed up by US air power.
The Taleban clearly decided not to contest Kabul and to withdraw their forces back to their heartland around Kandahar.
This does not mean that the war is over. The battle for the south may just be beginning.
But at this stage it is very difficult to determine the Taleban's losses in men or equipment. What is clear is that the Americans will be wanting to maintain the military pressure from the air.
How important was the Russian help for the opposition forces?
Reports indicate that the Northern Alliance has received some new armour and equipment from Russia.
The quantities may not be huge, but even relatively small amounts make a difference to the military balance in Afghanistan.
However, it is the wider Russian role and especially the new relationship between Moscow and Washington that has to a large extent provided the context for the Americans to wage this campaign.
Who will look after security in Kabul?
For the moment it seems to be in the hands of a small number of Northern Alliance forces, although it seems unclear if one can speak of any real security force at all.
One idea is to get some sort of international monitoring force into the city, perhaps under UN auspices and perhaps drawn from Muslim countries like Turkey.
Frantic diplomatic efforts are under way to try to find some sort of interim solution.
How far can we expect the Northern Alliance troops to go?
It is unlikely that the Northern Alliance will have much desire to carry the war into ethnic Pashtun areas in the south, as it might well be counter-productive.
The Americans want to win over those Pashtun groups to give a broader base to any new governing coalition in the country.
Pakistan has a clear interest in encouraging some of these groups to defect from the Taleban.
But if internal dissent does not lead to the collapse of the Taleban in the south, then US ground operations may be needed.
If the Taleban regime is to be defeated, the Americans have to beat it in its heartland around Kandahar. And it is predominantly in the south that the al-Qaeda group of Osama Bin Laden has been based.
Is a post-war political settlement any nearer?
No, and this is one of the problems that has dogged US strategy from the outset, the inability to keep the diplomatic and the military sides of the campaign in step.
Clearly, though, what is needed on the political front is a clear indication that key Pashtun leaders are willing to come over to the US-backed side in order to form a broadly based government.
Where does all this leave the hunt for Osama Bin Laden?
One part of the air campaign has been the attacks not just on al-Qaeda training camps but also on cave systems that are thought to be sheltering Bin Laden and his followers.
As the war turns against the Taleban it becomes possible that somebody who knows where he is may betray his location.
But the hunt for Bin Laden may only move into high gear once more of the country is in the hands of groups friendly to the US.