The best hope for an end to the killing in Syria is for the United States and Russia to push both sides in the conflict to agree a ceasefire in which each holds the territory it currently controls. In a civil war of such savagery, diplomacy with any ambition to determine who holds power in future will founder because both sides believe they can still win.
There appeared to be an opportunity for productive talks after it was announced on 7 May that the US Secretary of State, John Kerry, and his Russian counterpart, Sergei Lavrov, had agreed to hold a peace conference on Syria in Geneva. The US, Russia and Iran could see themselves being sucked into an ever more violent conflict and one that is rapidly spreading. It is destabilising Syria's neighbours in Jordan and Lebanon as Shia and Sunni support opposing sides. Even Turkey's new-found prosperity is vulnerable as a result of its whole-hearted backing for Syria's rebels.
However, the chance of any talks taking place in Geneva have dimmed in the past few days. The Syrian opposition has rejected the idea, though its intentions are very much determined by its paymasters in Saudi Arabia and Qatar. Going by the evidence of their own leaders, the rebels, inside and outside Syria, are so divided and dysfunctional they may not be in the business of talking to anybody.
Even if the opposition were better organised, they might still not want to talk. One of its leaders said: "We have to make the removal of the regime fundamental to any political solution." This may sound obvious, but an unstated part of opposition policy is that they can only win if the West and its allies among the Sunni states of the Middle East decide on massive military involvement to remove President Bashar al-Assad. They want a Libyan-type solution in which Assad would be overthrown, as was Muammar Gaddafi by Nato in 2011, with the rebels conducting a well-publicised mopping up.
However, the truth is that Assad was never as politically or militarily weak as portrayed in the international media or, until a few months ago, by foreign leaders. After two years of war he holds almost all the main cities and towns of Syria and the inner core of his regime has held together. This has become more evident in the past two months, as government forces go on the offensive and make limited but definite gains.
Foreign perceptions have changed. Six months ago, German intelligence was predicting Assad's fall. Now, it has been publicly saying it expects the government to secure its grip on Damascus and all of southern Syria by the end of the year.
The White House has said in the past few days that its top priority in Syria is to impose regime change, but this is a recipe for a very long conflict. Why should Assad and his government surrender when they are more than holding their own on the battlefield? Moreover, Washington appears to have shut the door on the idea of Iran, a main player, attending Geneva talks. This again is unrealistic if the aim of negotiations is to end the fighting. And Britain and France are playing a small but mischievous role in ensuring the slaughter in Syria continues. By successfully ending the EU embargo on arms for the rebels they will not bring talks nearer, as they pretend, but make them unlikely to take place at all. The type of weapons they will send are not going to tip the military balance. Government forces are too strong for this. The current stalemate is too well rooted in realities on the ground. The most significant impact of more arms for the rebels will be to persuade them that, if they refuse to negotiate, they will eventually get full-scale Western military intervention such as a Libya-type no-fly zone, which, in practice, meant Nato air forces joining the war.
It may be that Russia announced that it was selling Syria a sophisticated S-300 anti-aircraft missile system precisely in order to block this. By offering more arms, the EU will also be putting off the day when the two sides talk to each other through mutual exhaustion and the knowledge that neither can win.
At this stage, mutual hatred is too great for any long-term deal on sharing power. Everybody is caught up in what we used to call in Belfast "the politics of the last atrocity". Power-sharing would be geographical, with each side holding its own territory.
The first priority should be for the US and Russia to compel the sides they back to cease fire. This would have to be policed on the ground by a UN observer force. I recall the much-maligned UN Supervision Mission in Syria in 2012 arranging a ceasefire in the hardcore rebel town of Douma on the outskirts of Damascus. It did not stop all the shooting but many Syrians lived who would otherwise have died.
There may be a more sinister reason why the US has started setting the bar so high for talks. Washington's involvement is greater than appears because so much of it goes through Qatar, with the CIA determining who gets arms and money sent via Turkey. This would also explain why Britain and France are so keen to send the rebels weapons.
The explanation for the actions of the Western states may be that they do not want the war to end except as a victory for their allies. This certainly is the view of many in the Middle East, such as Mowaffak al-Rubaie, the former Iraqi National Security Adviser, who told me the civil war "is the best option for the West and Israel because it knocks out Syria as an opponent of their policies and keeps Iran busy. Hezbollah is preoccupied by Syria and not with Israel. Turkey's idea of a new Ottoman empire is gone with the wind."
This is a cynical but probably correct explanation for why the US, Britain, France and the Sunni monarchies do not want the war to end until they can declare victory.