Robert Mugabe’s decision to ban relief for his desperate citizens infringes every canon of human decency.

It puts the Zimbabwean government – perhaps too dignified a term – beyond the regimes even of Burma and Sudan in callousness. The crude device of state food for votes is a direct challenge to world sympathy, and to those who believe that such sympathy should be more than a collective cry of woe, and should motivate action.

The human tragedies still being experienced in the Irrawaddy delta and in the deserts of Darfur are now unseen. They have vanished from the world’s screens, as old news is not news. Rulers in these countries have stopped the wellsprings of global reaction at their source, that of publicity.

We therefore hear no more about international forces being sent to protect villagers or separate forces in Darfur, or to stop their children being sold into slavery. We hear no more about pressure on Burma to admit aid convoys. Last weekend Robert Gates, the American defence secretary, said he would not confront the “criminal neglect” of the Burmese generals; indeed he would withdraw the flotilla of aid ships waiting just miles offshore from some 2m people facing disaster.

Without the oxygen of information, humanitarian sentiment loses its anger and becomes just a dull ache. It can no longer override considerations of state sovereignty and the natural caution of diplomats and generals.

Zimbabwe, however, is still news.

That country’s ragged cloak of democracy has kept it in the world spotlight. Its brutal rulers still hold elections of sorts and tolerate a minimal level of political opposition.

Mugabe is even believed to have been on the point of standing down two months ago, after losing a presidential election to Morgan Tsvangirai, the opposition leader. He was dissuaded from cutting a deal on his future safety by his security and police chiefs, who were terrified of what less benign fate might await them.

Now Zimbabwe is in chaos.

People are uprooted, property confiscated, houses burnt, aid workers banned, opponents of the regime killed or mutilated and foreign diplomats arrested and their staff beaten. Tsvangirai is under a rolling arrest.

While the capacity of a subsistence economy to withstand collapse is always impressive, Zimbabwe is held back from mass starvation only by the flight of a quarter of its people beyond its borders. There is no way Mugabe is going to risk losing this rerun election.

Where now are the fine words of the international community in the Noble Nineties, boasting what Tony Blair called “the new doctrine of humanitarian intervention”? He declared in 1998 to rousing applause that the world order “could not turn its back” on flagrant “violations of human rights within other countries . . . Success is the only exit strategy I am prepared to consider”.

We are older and wiser now but the germ of a widely accepted idea remains. Today’s world is indeed reluctant to stand by when large numbers of people are dying as a result of the deeds of alien regimes, however sovereign. It did not leave hundreds of thousands of Kurds, Kosovans or East Timorese to be driven from their homes or to their deaths but mobilised opinion to aid them.

Even where the concept of such intervention was corrupted and abused, as in the invasions of Afghanistan and Iraq, it is to humanitarianism that apologists for these ventures still resort for justification. These countries must be occupied, they say, to save their people from a fate worse than self-determination. Humanity requires it.

This noble cause has vanished in the wind. Almost before it is put to the test it is gone. The failure to intervene in Darfur and the deference shown to the dictators of Burma and Zimbabwe indicate a pendulum swinging fast in the other direction. In Bangkok, Gates excused his inactivity in Burma on the grounds that “there is a great sensitivity all over the world to violating a country’s sovereignty”. That is novel from an occupant of the Pentagon.

Experts reply that intervening in Darfur would be “logistically difficult”. It would involve taking sides in what is essentially a civil war. That did not stop intervention in Kosovo. Experts say that in Burma intervention might have done more harm than good by alienating an already brutal regime. That did not stop us going into Somalia. Experts claim that Zimbabwe is really very complex, rooted in the politics of southern Africa and not our business. Such niceties did not impede the invasion of Afghanistan.

There is strength in all these objections, but so was there to the belligerent interventions of the George Bush/Tony Blair era. These leaders trumpeted that logistical (not to mention legal) obstacles to saving lives were there to be overruled. Sovereignty was no longer sacred. Force was all. Success was the “only exit strategy”.

After the cold war, the western nations led by America unashamedly took on the mantle of global supremacy. They were allowed to do so by many who might have questioned it, notably in Europe, Russia and China.

America’s leadership was soon debilitated in the quagmire of Iraq and Afghanistan, but the assumption of supremacy remains on the shelf.

This November the American presidency changes. If one message unites John McCain and Barack Obama it is that America’s image and its performance on the world stage are woeful, undermining its capacity to lead. Both men recognise that change is impossible without military disengagement from the two principal theatres of conflict, of which Afghanistan is becoming more intractable than Iraq. These adventures have come to pit America, the West and Christianity against Islam and the developing world. They have poisoned the well of America’s global leadership. The damage done to the moral authority of the West will be lasting and hard to repair.

For either McCain or Obama to find a path from Iraq that does not look like capitulation to Iran’s extremists will be hard. “Confronting Iran” has become a subset of defending Israel, requiring of Obama last week a ringing declaration that he would do “everything in my power to stop Iran obtaining a nuclear weapon . . . everything”. What that means is unclear.

Such belligerence may be required of those running for office, and Obama’s statements on foreign policy have sometimes seemed uncertain, but his awareness of the need for a course correction is unmistakable. If president, he must preside over what may seem an American retreat, though, as Nixon found in Vietnam, ending an unwanted war need not be unpopular. What is clear is that he and McCain know that until withdrawal is achieved, global consent to America’s world leadership will be on hold.

In other words, military disengagement is becoming conventional wisdom. For all the bold words on Iran, any further entanglement could hardly be less fashionable in Washington.

So where does that leave our old friend, humanitarian intervention? The concept was certainly oversold. In Lebanon, Kosovo, Somalia and Haiti it was heavily media-inspired and left the underlying cause of catastrophe unresolved. It failed the Kantian test of moral deterrence, that it must be seen as universally applicable. The West simply cannot appear with guns at the ready at every scene of human tragedy. As for deterrence, that has always been a game for armchair strategists. Did Kosovo deter the Burmese generals, or Lebanon the Somalian warlords?

It may be that there is nothing we can do about the horrors of Darfur, Burma or Zimbabwe, or nothing that could make their plight any better. It may indeed be wiser to sit on our hands and leave it to our leaders to emit occasional howls of impotent contempt, like the Foreign Office’s postimperial lament that some or other part of the world is “unacceptable”.

Yet I am sure that the concept of humanitarian intervention, however limited, was sound. Willing coalitions should be able to enforce the relief of suffering where relief is feasible, as was surely the case in Burma. For the time being, the blood-soaked gutters of Baghdad and the poppy fields of Helmand have taken their toll. They have rendered the entire concept of intervention defunct. It will take decades to recover.

simon.jenkins@sunday-times.co.uk

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