Leading article: Zimbabwe needs more than quiet diplomacy

The recent history of Zimbabwe has felt like a series of false dawns. Hopes that Robert Mugabe's cruel and chaotic rule might finally be over have been repeatedly dashed, as the old dictator moved ruthlessly to steal the election he had so obviously lost. He deployed a formidable array of sly tactics: invasions of white farms, arrests of election officials, bogus recounts and campaigns of intimidation in areas where the people had dared to vote against him. And yet it seems that the tide has finally turned against him.

Key in this change has been South Africa's leader-in-waiting, Jacob Zuma, who arrives in London today for talks with Gordon Brown before moving on to meet the French President, Nicolas Sarkozy, and the German Chancellor, Angela Merkel. Mr Zuma, in his toughest comments to date, yesterday called on African leaders to move in to unblock the Zimbabwean logjam. The remarks come all the more powerfully from the man who is now head of the African National Congress and the front-runner to take over as South Africa's president from Thabo Mbeki, whose "quiet diplomacy" approach is increasingly seen as discredited at home and abroad.

To be fair, Mr Mbeki had his moment. It was his initiative which changed election rules in Zimbabwe, requiring the results of each count to be nailed to the door of each polling station. That was what made it clear to the world, despite Mr Mugabe's attempt to stifle the result, that he had roundly lost. But quiet diplomacy has had its day. Mr Brown realised that when he spoke out against Mugabe vote-rigging at the United Nations, in a marked departure from the silence Tony Blair kept for fear that public condemnation merely fuelled Mugabe's rants about how everything was a plot by the British. A new momentum is clear all across Africa.

The President of Zambia has just urged Angola to turn away a ship carrying Chinese arms for the Mugabe regime, which South African trade unions refused to unload in Durban last week. Kenya's new prime minister has appealed for African heads of state to use force if necessary to remove Mugabe from power. The African Union has this week added its voice to the chorus of disapproval; its current chairman, the President of Tanzania, is pressing within the AU and the Southern African Development Community for action. All of that is far more important than condemnations from Western nations.

It is significant that, though the South African High Court suspended the Chinese arms shipment's conveyance permit, it was the nation's transport union, Satawu, which led the fight against allowing weapons to the Zimbabwe regime. Satawu was a key force in the struggle against apartheid. It is also now an important ally of Mr Zuma, whose power base is mainly among the trade unions. Zimbabwe's rightful president, Morgan Tsvangirai, whom Mr Zuma went out of his way to meet – in contrast to Mr Mbeki – is a former trade unionist, too. He is also, like Mr Zuma, of Zulu tribal origin.

There is a power struggle between Mr Mbeki, who steps down as president next year, and Mr Zuma, his former deputy. Its outcome is not absolutely certain; for eight years, Mr Mbeki has spared no effort in trying to nail Mr Zuma, with charges of tax evasion and rape which Zuma supporters say were trumped up. He was acquitted of rape but faces a corruption trial in September. If Zimbabwe is one of the key cards in the poker game between the two men, that could yet work to the advantage of Zimbabweans. Mr Zuma knows that if he can broker some kind of resolution in that benighted nation, it will go a long way to alleviating concerns in the international community about his leadership ability.It will raise his political stock at home and throughout Africa. Change for Zimbabwe may, after all, be unstoppable.