Most crises blow over. A few blow up. But one or two live in our memories, scars on the conscience of a world that had knowledge of tragedy, the capacity to intervene, yet failed to act.
Zimbabwe is no Rwanda. Not yet. But after enduring years of Robert Mugabe's thuggery, it has another cross to bear. The country is weeks away from what could become a catastrophe. Already more than two million people need food aid in what, say officials, is a “very, very serious” situation, after the collapse of commercial agriculture in the wake of Mr Mugabe's confiscation of white-owned farms. By early next year famine could threaten the lives of some five million people - nearly half the population.
Yet Zimbabwe's agony is all but buried under the international avalanche of bad financial tidings. But one suspects that the country is out of the headlines for another reason. The international community has turned away, well aware that horror may be imminent, but reduced to embarrassed silence by its failure to act decisively.
Every now and then, however, there comes a point in a crisis where the scale and duration of the suffering become too much to ignore. Conscience is pricked, and a hitherto bemused world wakes to demand action.
That point has surely been reached in Zimbabwe, where the testimony of a nurse in the front line (who of necessity must remain anonymous) suggests that her country has reached the end of its tether. She has spent 30 years serving its people, and now helps to run a city hospital. But never in all that time has she felt such painful frustration at the sheer scale of the agony unfolding. And it is coupled with anger at what she sees as the bureaucracy of a leading international aid agency in the face of pleas from the desperately needy.
Applicants for help from the UN World Food Programme (WFP), she writes in an e-mail, “are meant to declare how many are in their households, how many are disabled, how many are chronically ill”.
Food for the starving is available, she says, held in the local compounds of the WFP, ready for distribution. But first, insist officials, comes the paperwork: tick the right boxes on two vital forms, and you qualify for help. Give the “wrong” answers and you will almost certainly starve.
“Just how,” she asks, “does the head of a child-headed household [an all too common phenomenon in a country decimated by Aids] get into contact with people who have the questionnaires? We have had people in their hundreds coming to our doors and pleading for food.
“Please, whoever is responsible for all the bureaucracy, end this expensive time-wasting exercise. We plead with you to start getting the food out of the warehouses to the people who are hungry.”
One can sympathise with the WFP position: that in time of acute need scarce resources must be safely stored, and criteria for their release drawn up and observed. Nor should the delicate nature of a relief agency's balancing act be underestimated: for how long should it abide by an agreement with a noxious regime, in which restrictions on relief operations have been reluctantly accepted, in the belief that the lifesaving role it plays outweighs all else?
The evidence of the nurse and others, however, suggests that whatever the terms, the deal is not working. In her city, youngsters beg for food at the hospital gates. In the country, many Zimbabweans are reduced to eating roots in the worst- hit areas, according to a BBC report last week.
This leads to an obvious conclusion: conventional means of supply and distribution are not enough. Zimbabwe urgently requires the unprecedented: a unilateral airdrop of food and medical supplies.
The means are within reach. Giant Hercules aircraft, of the sort used by the UN in Ethiopia and Sudan, could be based in neighbouring Botswana, where President Khama has shown he is willing to stand up to Robert Mugabe.
True, in the all too likely absence of government consent, the airlifted supplies would reach a fraction of those in need; and the dropping points would be arbitrary. But not a single life need be lost in the conduct of the operation, and many thousands would be saved.
Readers may recall a passage from Albert Camus' The Plague. The Algerian town of Oran is isolated, cut off from the world by the dreadful pestilence it endures, and at night the local doctor reflects: “From the ends of the Earth, across thousands of miles of land and sea, kindly, well-meaning speakers tried to voice their fellow feeling, and indeed did do, but at the same time proved the utter incapacity of every man truly to share in suffering which he cannot see... ‘Oran, we are with you', they called emotionally. But not, Dr Rieux told himself, to love or die together - and that's the only way. They're too remote.”
Zimbabwe is indeed a long way away. But it is not so remote that we cannot demonstrate our compassion, as well as our outrage, in a form that provides some relief to its people - even if we cannot truly share in their dreadful ordeal. If not an airdrop now, when? And if not an airdrop, what?
Michael Holman, a former Africa editor of the Financial Times, grew up in Zimbabwe. His latest novel is Fatboy and the Dancing Ladies (Abacus)