Leading article: The lesser of two evils

Morgan Tsvangirai is a political realist. That is why he decided, in the end, not to stand against Robert Mugabe in last week's bogus election in Zimbabwe. Too many of his supporters and – when they went into hiding – their wives, were being killed in the run-up to a polling day whose result he well knew would be rigged by a man determined not to relinquish office to any power less than the divine. Mr Tsvangirai is a brave man but he is not foolish.

He also knows that, in the end, the solution to the crisis can only come through negotiation. There will be no outside military intervention. And practical politics means creating the space in which his blood-soaked opponents – Mr Mugabe and his half dozen iron henchmen – can extricate themselves without facing an international human rights tribunal and, perhaps, even retain a modicum of prestige, if not power. That outcome will not suit high-minded idealists, but if Mr Tsvangirai had been that he would have persisted with the election whatever its murderous consequences for literally thousands of his supporters.

But he is right to take a tough line on two preconditions for negotiations for the government of national unity which African Union leaders proposed at their Egypt summit. The first is that, whatever the name given to the outcome, it should be clear that this is a transitional arrangement designed to lead to new elections; it must not be a continuation of the Mugabe regime with a few opposition MDC ministers included in the cabinet. The second is that Thabo Mbeki cannot continue to be the sole mediator in such negotiations.

Mr Mbeki's credibility is now shot. It is politically unrealistic to expect him to stand down but he must now be joined by a co-mediator of equal political weight, but one who is not partial to the Mugabe cause; ex-Presidents Chissano of Mozambique or Obasanjo of Nigeria would be credible, as would Graca Machel or Kofi Annan.

The public result of the African Union summit looked good for Mr Mugabe but in private he was shaken by the reception he got from the leaders of Botswana, Nigeria, Liberia, Sierra Leone, Zambia, Kenya and even Uganda who, for the first time, spoke critically to his face. The AU president, Jakaya Kikwete, at one point cut the despot off as he was speaking. Mr Mugabe's cronies now know the writing is on the wall. Moves by the US and UK to press for an international arms embargo and further sanctions are adding to the pressure. It is the right time for Mr Tsvangirai to begin negotiations, but he can afford to be tough in them.