Leading article: A diplomatic gamble that has only made matters worse

The rejection by the United Nations Security Council of a resolution to impose sanctions on Robert Mugabe's regime leaves us in the worst of all worlds. The international community looks divided and irresolute over the crisis in Zimbabwe. Meanwhile, Mr Mugabe himself has been able to hail the failed resolution as a personal triumph and a defeat for "international racism".

The resolution's failure certainly overshadows the fact that several of Mr Mugabe's neighbouring states are refusing to recognise him as president; an unprecedented rupture of the informal rule that African governments do not turn on their own. And it weakens the position of the opposition Movement for Democratic Change in its negotiations with Mr Mugabe's Zanu-PF party. The thwarted resolution feels like a return to square one.

Russia and China vetoed the resolution at the Security Council meeting in New York, arguing that Zimbabwe poses no threat to international security. The US says Russia's behaviour brings into question its reliability as a G8 partner. Our own government, which sponsored the motion along with Washington, says the vetoes are "incomprehensible". Actually, the result was only too comprehensible. Russia and China have a long history of vetoing resolutions against nations that confine their abuses to their own borders.

It was a diplomatic blunder for Britain and the US to force a vote on this resolution without being reasonably sure of a positive result. If its passage could not be guaranteed, it should never have been put forward. The US and UK seem to have misread Russia's acquiescence in last week's G8 summit communiqué, which said that "steps should be taken, including financial and other measures against those individuals responsible for violence" in Zimbabwe. Britain and America thought this meant sanctions. Russia, evidently, did not. But while the vetoes of Russia and China might be explained away as a last-minute betrayal, the no vote of South Africa, one of the non-permanent members of the Security Council, points to a broader failure to prepare the ground. The British Foreign Minister for Africa and former UN diplomat, Mark Malloch-Brown, has described the resolution as a "high-stakes gamble". But, in diplomacy, gambling tends to be unwise. And when the result affects the lives of hundreds of thousands of Zimbabweans, it begins to look positively irresponsible.

Yet though the execution was appalling, the intention was sound. South Africa argues that sanctions would interfere with the negotiations in Zimbabwe and risk provoking a civil war. This is wrong. The UN should be unequivocally backing the MDC in these power-sharing talks through the threat of sanctions. An arms embargo and an international travel ban on the country's ruling clique would have helped to force Mr Mugabe to meet the MDC's demands.

What is the alternative? The "quiet diplomacy" of the South African president, Thabo Mbeki, over the past eight years has failed. There is no reason to believe it will start to bear fruit now. As for Mr Mbeki's fear of a civil war in South Africa's northern neighbour, he needs to take a closer look at how the political opposition is being terrorised by Mr Mugabe's thugs. The conflict is already spiralling out of control.

Russia and China are also wrong to argue that what is happening in Zimbabwe should be treated as an internal matter. This is merely an excuse for turning a blind eye to the horror that Mr Mugabe is inflicting on his own people. After last week's shambles, the international pressure for this blood-soaked tyrant to step down needs to be redoubled, not eased.