The crucial point about the search for a diplomatic settlement is that it has been in pursuit of two goals: first, a G8 plan backed by Russia and the West that will form the basis of a United Nations resolution setting out the essential framework of a Kosovo settlement - and acceptance of that plan by Mr Milosevic.
Yesterday's "agreement" was as good as it is going to get on the first point. But if no deal can be reached with Mr Milosevic, the one with the Russians could unravel as well.
If there are doubts about what has been agreed with the Russians, there are none about where disagreement lies between Mr Milosevic and the West. Beyond the matter of a halt in the bombing, which would become moot if Mr Milosevic signs up to the peace plan, two key issues remain unresolved: the make-up of the peace-keeping force in Kosovo and the size of the contingent Serbia could maintain there.
A chasm divides the sides. Nato appears unshakeable on its demands that at best a few hundred Serb troops could be allowed, and then only after a full withdrawal; and that the allies provide the core of a peace force. Belgrade wants the full 16,000 Serb force provided for by the abortive ceasefire deal of October, and will at best countenance only Nato forces from countries which have not taken part in the bombing.
So where do the Russians stand? Nato has insisted it will not abandon its "five principles" to strike a bargain with Russia. "Of course we want to bring the Russians into this - but on our terms," a US official said. If so, the real question is, therefore, to what extent has Moscow embraced the West's terms?
On the record, alliance diplomats say it has been edging closer to Nato's position. But the absence from the final press conference in Bonn of Strobe Talbott, US deputy secretary of state and the third participant in the talks, suggests latent areas of dispute which a little scratching could easily expose. And in this field there are few more skilled practitioners than Mr Milosevic.
Officially too, Nato insists the meeting in Belgrade will not be a negotiating session; the Russian envoy, Viktor Chernomyrdin, and the West's representative, Martti Ahtisaari, will explain the offer. The rest, says the alliance, is up to Mr Milosevic. Would it were so simple. For what if he responds with a counter-offer, acceptable to the Russians but not to Mr Ahtisaari? What price then the G8 holding together?
Ah yes, say the allies, but the air campaign has wreaked so much damage that even his generals are urging Mr Milosevic to accept the package. But is this not the same alliance which, two months ago, was saying a few days' bombing would make Mr Milosevic see reason? For all the pressure on him, he may yet reckon Nato's talk of a ground war is bluff - and that well before Yugoslavia's back is broken Western public opinion will have turned against the air war.
Last night the potential stumbling-blocks were obvious, none more so than Kosovo's partition. Nato insists it is out of the question, as it would reward "ethnic cleansing". Mr Chernomyrdin's talk of separate groups of Russian and Nato soldiers under separate commands may be a sop to the nationalist lobby back home.
But it could equally easily be interpreted as a first step towards "sectorisation" along the lines of post-war Germany. That is just one Russian-Nato fault- line for Mr Milosevic to scratch on.
1. The immediate and verifiable end to Serbian repression in Kosovo
2. Withdrawal from Kosovo of all Serbian police and military forces
3. Deployment in Kosovo of an effective international security presence endorsed by the UN
4. Establishment of an interim government in Kosovo, to be decided by the Security Council
5.The safe return of all refugees and access for aid agenciesReuse content