Last week Mr Kabila, based in the eastern town of Goma, gave Zaire's veteran dictator three days to resign or leave the country. "If he asks me politely I cannot refuse to talk to a com- patriot," said Mr Mobutu, "but to be in Goma and say I give him three days, it's not my style or nature. I cannot reply. This kind of joke will backfire ... I am head of state."
In recent weeks, however, Mr Kabila's rebels have seized the diamond, cobalt and copper-producing areas that made the president one of the wealthiest men on the planet, and now claim to be within 200 miles of the capital of Africa's third-largest country.
In Kinshasa itself the opposition has rioted on the streets. Mr Mobutu's former cold war allies in the US and Belgium have told him that it is time to go. Yet in his few recent public appearances, the ailing president continues to wear his trademark leopardskin hat over a smug smile. Like a career criminal, he still seems to get a thrill from having got away with it for so long.
Mr Mobutu's rule goes back to the bloody and confused years that followed Belgium's withdrawal from the then Congo, a time of secessionist wars in Katanga and civil wars in the east, when white mercenaries fought against the government in Kinshasa - then called Leopoldville - then switched sides to help it impose its will on the ramshackle giant of central Africa.
From the start Mr Mobutu depended for his survival on foreign clients. The coup which brought him to power in 1965 was engineered by the CIA, which was eager to finish off the left-wing Congo state founded by the assassinated Patrice Lumumba. For the US, France and Belgium, Mr Mobutu was a staunch cold war ally against Marxism and the man with whom their mineral companies could do business.
In return for his co-operation, particularly against the Marxist government in Angola, Western countries were prepared to ignore his faults. Apart from the rampant looting of the national treasury, these included a tendency to torture or murder political opponents and using his undisciplined army as a crude instrument of terror against the civilian population.
Nguz Karl-i-Bond, a former Katangan leader who defected to the rebels last week, once claimed publicly that he is impotent because of electric shocks administered to his testicles by Mr Mobutu's police. It is a tribute to the president's undiminished ability to seduce - and to the supreme corruptibility of Zaire's political class - that Mr Karl-i-Bond subsequently agreed to become Prime Minister in 1992, and remained Mr Mobutu's official election agent up until his defection.
But Mobutu's principal victim was the state he had personally founded and named, Zaire. While ordinary people slid ever deeper into poverty, Kinshasa became the international base for an obscenely wealthy bandit caste - the so-called kleptocrats. In 1989 the US State Department estimated the president's wealth at $5bn - a sum then equivalent to Zaire's national debt. While patients in public hospitals had to pay up front for every injection, Mr Mobutu owned four gold-plated bullet-proof jackets, and had property in Belgium, France, Switzerland, Spain and the Ivory Coast.
The end of the cold war might have appeared to mark the end of the party. The US could no longer turn a blind eye to Zaire's corruption and deplorable human rights record, and in 1991 when Mr Mobutu balked at pressure to introduce democracy, aid was cut off. He was refused a visa to visit the US, and even his closest ally, France, seemed to be losing patience. In 1991 and 1993 his attempts to get out of financial trouble by issuing new banknotes prompted the army to mutiny and pillage Kinshasa and other major towns.
But the durable president clung on, and three years ago he had a stroke of luck. The Rwandan genocide and the subsequent flight of more than a million Rwandan Hutus into Zaire meant the West suddenly needed Mr Mobutu again, to provide the air strips and security for the world's most concentrated relief effort. He was quickly rehabilitated as a man of peace and compassion.
But if Rwanda saved Mr Mobutu in 1994, it has since proved to be his undoing. His ties to Rwanda's deposed Hutu regime, and the persecution of Zaire's own Tutsis helped to touch off the revolt against him. Mr Kabila's forces now control the eastern half of Zaire, including all the fertile and mineral-rich parts. All of a sudden Kinshasa has no mineral wealth left to loot, and Mr Mobutu has no power beyond his capital.
Last week he reverted to military rule, sacking the opposition's civilian prime minister designate, Etienne Tshisekedi, beating his followers off the streets and replacing him with a military hardliner, General Lubulia Bolongo.
Most ordinary Zaireans will be glad to see him go, believing that Mr Kabila, although still largely unknown, can hardly fail to run the country better. But when one looks at some of the other African leaders Mr Mobutu has survived, it appears - extraordinarily enough - that he could have been a lot worse.
His security forces bullied, stole, tortured and murdered, but at least they did it with a material end in mind. In a time and place that fostered mass murderers like Uganda's Idi Amin, the Central African Republic's Emperor Jean-Bedel Bokassa and the Rwandan Hutu militias, that is worth bearing in mind. Compared to these psychotics, cannibals and genocidaires, Mr Mobutu seems like an ordinary decent criminal.Reuse content