Nato's air campaign appears to have achieved a historic victory, at least in military terms.

This is the first time that precision-guided weapons have been used on this scale. The campaign was seen as a critical test for modern air power.

But this was not a victory for air power alone.

From the outset of this campaign even many of Nato's principal commanders worried that their political masters had given them an impossible task.

They were confident that alliance air power could inflict terrible damage on Yugoslav forces in Kosovo and against Yugoslavia's strategic infrastructure.

But they were sceptical that air power alone could force the withdrawal of Yugoslav forces from the province.

Pressure for ground troops

Some bombs went astray

Military men wanted to see at least the threat of the use of Nato ground troops. But that was ruled out by most alliance leaders as politically unacceptable.

Nato's campaign against strategic targets in Yugoslavia proved highly effective, although a small number of weapons inevitably went astray killing civilians, a factor that strained the alliance's cohesion.

But Nato also claims to have done serious damage to Yugoslav forces in Kosovo, especially during the last week.

Here of course air power found itself operating, if not in concert, then at least in parallel with units on the ground.

For it was the Kosovo Liberation Army's offensive that forced Yugoslav troops out of their hiding places.

And as they organised themselves to combat the KLA they became easy targets for Nato warplanes.

Backing diplomacy

It looks as though Yugoslav commanders became increasingly worried about how long their troops could take this punishment.

This provided the backdrop giving the European and Russian envoys' diplomatic efforts added weight.

Nato may have been increasingly war weary, but it showed no sign of relenting. And the indictment of the Yugoslav President Slobodan Milosevic as a suspected war criminal may have turned the balance in favour of a deal.