Acting as President in the absence of Nelson Mandela and his deputy, Thabo Mbeki, Buthelezi gave the order for 600 South African troops to enter Lesotho's capital Maseru at dawn last Tuesday and quash what was in effect a coup against Prime Minister Pakalitha Mosisili's government.
Six days later, not only has the operation to "restore law and order" led to at least 80 deaths, destroyed central Maseru and poisoned the intimate relationship between South Africa and the independent enclave of Lesotho but - like Shaka's 19th-century conquests - it could also have implications for the future stability of the entire region.
After thus dismally failing to resolve what seemed to be a relatively minor problem within its own frontiers, South Africa now has little chance of playing a positive role in the much more worrying conflicts in Congo, Angola and the rest of Africa.
From the first hours of the operation it became clear that the South African army - which used to raid Maseru with impunity in the apartheid days - has lost its old ruthless edge. The initial force rolled up to the two main army barracks and the royal palace with little difficulty but soon found itself under unexpectedly heavy attack from armed opposition supporters and members of the mutinous Lesotho Defence Forces.
The supposedly ill-disciplined LDF - described by one diplomat as "the armed wing of the [opposition] Basotho National Party" - still managed to hold out for more than two days. Confronted by snipers on the main Kingsway and by angry opposition demonstrators at the royal palace, where King Letsie III preserved a stony silence throughout, the South African troops found that their rules of engagement left them powerless to intervene against the looters and arsonists who soon swarmed into the streets.
One South African corporal sat glumly in the roof-hatch of his Mamba armoured vehicle and watched as a mob looted and burned a department store. "There is nothing we can do but shoot in the air," he said. "We can only shoot at people if they shoot at us first."
By Wednesday, much of central Maseru had been looted and gutted. Meanwhile the South Africans had lost eight soldiers dead and more than a dozen wounded. The LDF was reported to have lost more than 50 dead and 190 captured before its members finally abandoned their main base, taking to the hills or melting into the civilian population. Foreign diplomats in Maseru now fear that they will continue bandit attacks in the interior for weeks, months or even years to come.
According to Tom Lodge, a political scientist at Johannesburg's Witwatersrand University, South Africa's first foreign military operation since the end of apartheid casts a poor light on an army that is still struggling to combine members of the old, white-dominated force with former guerrillas from the black liberation movements.
"The invasion seems to have been very badly planned and badly handled," he said.
"South Africa's stature as the region's professional and competent military power has taken a fair knock."
But the damage to South Africa's diplomatic reputation may be even worse. A Maseru-based diplomat said that by allowing what was essentially a petty power struggle between two political elites to escalate into a major armed confrontation, South Africa has shown a remarkable degree of ineptitude. "This must at the very least tarnish the reputation and expectations that South Africa would be a constructive and benevolent force for good in the region," he said. "If they really can't handle a dispute in a tiny place like this, how can they pretend to be able to do things better on a larger stage?"
South Africa had in recent months resolutely refused to allow Zimbabwe's President Robert Mugabe to drag the 14-member Southern African Development Community into military support for Congo's President Laurent Kabila. Now, not only has South Africa seemed to contradict its own policy of non-military intervention - although Lesotho's government, unlike Kabila's, is elected - but it has done so to disastrous effect.
As the smoke fades over what is left of downtown Maseru, attention will turn to how South Afria mishandled an independent report by a South African judge on the conduct of last May's elections in Lesotho - opposition claims that they were rigged is what sparked the crisis. South Africa, having first withheld the report for more than a week without explanation, then released it only to the country's squabbling political leaders and invited them to meet to negotiate a compromise.
Instead, the few remaining government ministers fled the country, fearing for their lives, and an opposition mob shut down the state radio station, leading to the military intervention.Reuse content