Robert Mugabe is finally facing a serious challenge. The Zimbabwean President's former Finance minister, Simba Makoni, has announced that he intends to oppose Mr Mugabe in national elections scheduled for next month. Mr Makoni declared yesterday: "I share the agony and anguish of all citizens over the extreme hardships that we all have endured for nearly 10 years now. I also share the view that these hardships are a result of failure of national leadership."

This represents a pretty unambiguous attack on Mr Mugabe. It was always likely that the first serious challenger would emerge from within the Zanu-PF Party. Zimbabwe's main opposition party, the Movement for Democratic Change (MDC), led by Morgan Tsvangirai, is weak and divided. And the state security services and militias of war veterans would rapidly crush a popular uprising. This might turn out to be a vindication of South Africa's policy of "quiet diplomacy" – working with Zanu-PF rather than the MDC – to try to resolve the crisis afflicting its northern neighbour.

Mr Makoni has no strong grassroots movement behind him, but if he can attract the support of the influential Vice-President Joyce Mujuru and her husband, the former army chief Solomon Mujuru, he has a chance of breaking the hold on power that Mr Mugabe has had for nearly three decades.

Of course, Mr Mugabe might see off the younger man. The President may have reduced his nation to an economic basket-case, but he has a formidable ability to undermine opponents and stands at the top of a huge patronage system. And, even if Mr Mugabe is deposed, Mr Makoni is hardly a desirable candidate to take over. Despite being referred to as a moderniser and a competent technocrat, as a member of Zanu-PF he has been close to Mr Mugabe for many years and is implicated in his disastrous and murderous misrule.

The new leader might adopt a saner economic policy, but there is no reason to believe that a Makoni election victory would result in a new flowering of liberty in Zimbabwe. What the country needs is not just a new ruler but a genuine multi-party democracy and a return to the rule of law.

At the moment, however, Mr Makoni looks very much like the lesser of two evils. And there is another reason to hope. History teaches that authoritarian regimes are often at their most vulnerable not when repression is at its worst, but when it begins to ease. If Mr Makoni's move signals the beginning of the end for the grotesque regime established by Mr Mugabe, those who care for Zimbabwe and its people should welcome it with open arms.