Leading article: A disastrous failure of leadership

The United Nations appears to be spinning, once more, into crisis. Inga-Britt Ahlenius, the outgoing head of the UN's internal corruption watchdog, has delivered a scathing "end of assignment" report in which she accuses the Secretary General, Ban Ki-Moon, of personally frustrating her work.

The allegations in the leaked paper certainly seem to fit a depressing pattern. Some of the UN's top internal investigators have departed in recent years and have not been replaced. And the watchdog's investigative unit has been instructed not to open cases of financial fraud or corruption involving former UN staff. This is the sort of behaviour one would expect from a nervous tin-pot dictatorship, not the world's foremost multilateral organisation. And, according to Ms Ahlenius, the rot comes from the very top.

Mr Ban was chosen as Secretary General three years ago in the wake of the Iraq oil-for-food corruption scandal, which tarnished the reputation of his predecessor, Kofi Annan. This unprepossessing Korean diplomat was charged with cleaning up the UN's image and pushing forward internal reform. But it would appear that Mr Ban's primary objective has been to avoid rocking the boat.

In any discussion of the shortcomings of the UN, it is vital to recognise that the organisation will always be a flawed organisation so long as the countries that make up its membership are flawed. To some of its critics, the UN is too exclusive, too slanted in favour of the richer nations. It is regularly attacked, in particular, for the unrepresentative nature of the governing Security Council. And yet when certain unsavoury regimes take up places on UN human rights panels, the organisation finds itself criticised for not being exclusive enough.

Something similar applies when the UN brokers deals. Horse trading is needed to get anything substantive done, whether that is delivering aid to closed states hit by natural disasters (like Burma in the wake of Cyclone Nargis), or getting approval for multilateral peacekeeping missions (as in Darfur). Yet it finds itself condemned for doing shady deals. The UN's curse is to be held to higher moral standards than its member states, while still expected to deliver results through consensus.

The UN also has powerful and vociferous enemies, not least in the United States, who seize upon its every failing. The real agenda of many of these critics is not to reform the institution, but to destroy it. It is vital that they do not succeed. The United Nations is, on balance, a positive force in the world. The G20 and the G8 are groupings of the powerful. The UN is the only forum in which the poor states of the planet have any sort of global voice.

But however many compromises the UN makes to keep the show on the road, one thing on which it simply cannot afford to compromise is institutional corruption. Corruption undermines the legitimacy that the UN draws from its inclusive approach. Everything worthwhile that the UN does – from impartial inquiries into the behaviour of nation states, to peacekeeping missions, to co-ordinating international efforts to counter climate change – depends on this legitimacy. That is why the oil-for-food scandal was so damaging. The UN must be seen as competent to police itself.

Whatever else Mr Ban's supporters claim he has delivered, on issues from women's rights to international diplomacy, when it comes to institutional reform and the fight against corruption he has been disastrously weak. The Secretary General's first term will come to an end at the end of next year. There needs to be nothing short of a revolution in Mr Ban's approach if he is to merit another.