Before Robert Mugabe voted yesterday, his enforcers had guaranteed him a victory of sorts by murdering at least 90 people in his name. They burned a six year-old boy alive in his home, along with his pregnant mother. Another woman was found horribly dismembered in her kitchen. Her crime: to have been married to an opposition councillor. Ten thousand people have been injured. Two hundred thousand have been displaced.

The repugnant image of Zimbabwe's dictator casting a ballot in his one-candidate re-election insults the memory of his victims. It compounds the suffering of their families and challenges the whole of Africa to condemn him out of hand at last, to isolate him and to end his country's nightmare by hastening his departure from power.

Africa's better leaders have a chance to shed their inhibitions and start this process almost at once. Mr Mugabe has vowed to attend the Africa Union summit at Sharm-el-Sheikh in Egypt on Monday, there to confront anyone brave enough to denounce him and “see if those fingers would be cleaner than mine”. His point is well taken. Too many AU member states are still pernicious kleptocracies with little to boast of by way of democracy. From the Republic of Congo to the summit's host country, led by the repressive Hosni Mubarak, misrule is the rule (see page 6).

But there are exceptions that keep hope alive. Ghana, Botswana, Namibia and South Africa enjoy rankings comparable with some of the EU's newer members in a global survey of democratic institutions. Botswana and South Africa beat Slovakia and Greece in international corruption rankings. In Africa as elsewhere, there is a clear, positive correlation between strong democratic credentials and strong economic growth rates, and the countries that lead these tables are leading a growing chorus of denunciation of the terror that Mr Mugabe is inflicting on his people.

Without waiting for the lead offered by Nelson Mandela in London this week, President Levy Mwanawasa of Zambia said that for Zimbabwe's neighbours to stay silent on its suffering would embarrass them and the entire continent. Botswana has given warning that it may not recognise the result of an election from which Morgan Tsvangirai was forced to withdraw for fear of further butchery of his supporters. The ANC has declared itself “deeply dismayed” by the violence (even if South Africa's President Thabo Mbeki has yet to see reality), and Tanzania's President has called the AU's silence so far on Zimbabwe “deafening”.

These statements come late. Mr Mugabe's wilful destruction of his country started eight years ago. But Africa is finally taking a stand and deserves recognition for it.

The AU must now heed Tanzania's warning and go much farther, by refusing to recognise either yesterday's blood-soaked parody of an election or the regime that will claim a spurious mandate for more power as a result of it. For the bleak truth is that Zimbabwe's plight eclipses every green shoot of good governance elsewhere in Africa. In the land of the six billion-dollar loaf, rampaging paramilitaries and remorseless Zanu (PF) “re-education” teams have turned the fertile heartland of southern Africa into a vortex of misery that is destabilising the entire region.

The AU's duty in the next 48 hours is clear. Zimbabwe's neighbours in the South African Development Community (SADC) have an even more vital role. They must unite to isolate Mr Mugabe and his inner circle. With their help, the world can tighten sanctions, targeting the few dozen men with the blood of so many on their hands. Without it, the shame that Mr Mugabe has heaped on his country will only spread.