Zaire is being swept up in yet another tragic cycle of the bloody rebellions and harsh repressions that marked its tortured beginning as a nation independent of Belgian colonial rule in 1960.

The hue and cry in Washington and other Western capitals about Cuban and Soviet machinations behind the latest invasion of Zaire's mineral-laden Shaba Province has made it seem as if outside powers were mainly responsible for the renewed troubles.

In fact, tribal and regional forces have pulled apart this Belgian-designed mosaic of a country, which pieces together some 200-odd tribes, for as long as it has shakily existed. Their strength has risen and ebbed over the years but never been totally harnessed.

At one point in the early 1960s, more of Zaire, then known as the Cargo, was under rebel than central government control. Katanga, then as now, was the center of the drama.

"This has been going on for 18 years now. It's going to happen again, too, you will see. These katangas will just keep on trying, I tell you. They fight even without eating."

Such in the popular view in the Zairian capital about the Lunda people of the old Katanga Province, now called Shaba - as if a change in name wish away a problem that has weighed on this rebillion-ridden central African country ever since its birth.

The determination of the Lunda-led Katangans to make their political comeback is coupled with their burning wrath against the central government. Probably twice as many blacks as whites died during their six-day occupation of the mining town of Kolwezi and not all died by accident. Some were hated officials from Kinshasa rounded up and deliberately killed according to Zairian sources.

After last year's 80-day Shaba war, tens of thousands of Lunda fled from the province into neighbouring Angola to escape the Zairian army's retaliation. Now that the army is back in control of Kolwezi once more, it is again taking its retribution in hosehold goods and lives from the civillian population and another Lunda exodus is certain.

There have been increasing signs recently that Zaire might well be on the verge of another political explosion as the deterioration in the economy reached alarming proportions. In the past few months, these have included a bloody local civillian rebillion, an army revolt and a plot to overthrow President Mobutu Sese Seko, all against the already upsettled background of last year's Shaba War.

As many, as 700 civillians were reportedly killed in the government's brutal suppression of the rebellion, 14 officers were executed in the army revolt and another 13 officers and civilians in the allerged plot.

At the same time, Mobutu carried out a sweeping purge of distrusted Lunda and Luba officers. Some reports say as many as 600 were retired from duty in March.

This followed the arrest, trial and sentencing to death last year of the best known Lunda in Mobutu's government, his former foreign minister, Nguza Karl-i-Bond. The president later spared his life but has left him in prison for his alleged complicity with the Shaba rebels.

The feud between Mobutu and the Lundas had taken on a struggle-to-the-death quality even before the rebels launched their latest Shaba campaign in mid-May.

The struggle of the Lundas for a place in the Zairian political sun has had a curious way of changing ideological colors, directions and goals over the years. At independence, the Katangas were right-wing "separatists" backed by Western, particularly Belgian, business interests. Katanga was more or less an independent state for two years before rejoining the rest of the Congo.

Today, The Lunda-led Katangas have garbed themselves in the robes of "national liberators," taken on a new and more respectable "anti-neocolonialist" language, set as their aim Motubu's downfall and found new supporters in the Communist East and among its African allies.

It was a strange combination of Western resolve, United Nations action and white mercenary military might that first stamped out rightist and leftist rebillions and sucessionist bids and imposed by 1965 a semblance of national unity on black Africa's second largest land mass within one border.

Ironically, it was the Katagan Lunda leader, Moise Tshombe, who led in the first splitting apart the Congo and later reunifying it. After heading the Katanga secessionist movement until it collasped in early 1963, he returned to become the Congo's prime minister a year later.

While Tshombe still held the reigns of national power in November 1964, the United States and Belgium acted together to successfully quash a serious leftist challenge to the central government from the northern city of Kisangani, then Stanleyville. Then as today the Western pretext for direct military intervention was whites trapped in a town under rebel control.

A year later, in November 1965, Mobutu pushed aside Tshombe and took over a country exhausted from its internal political turmoil and repeated rebillions. With strong Western backing, he kept the loosely knit parts of the country together through a combination of tough authoritarian rule and the offer of lucrative rewards, government posts or businesses to his opponents.

Meanwhile, the ethnic base of his regime bacame increasingly the peoples from his own northwestern Equateur Province with his most trusted guards and soldiers drawn almost exclusively from there or the prospering Kinshasa region.

Yet pockets of resistance to the central government under Mobutu survived in remote corners of the country. One of these was in Shaba Province where the remaining survivors of the old Katangese police force had taken refuge just across the border in then Portugese-ruled Angola and were biding their time for revenge.

Another was in far eastern Zaire along Lake Tanganyika where a group calling itself the People's Revolutionary Party and claiming to be Marxist has held out for over a decade in its jungle redoubt. Its continued existence came to light in 1975 when four students, several of them Americans, were kidnaped by these rebels from the Stanford University-supported Chimpanzee Gombe Research Center in Kigoma, Tanzania.

It seems not without significance now that prior to the latest Shaba troubles there were several other local rebellions that were brutally suppressed by the Zairian army but went practically unreported in the Western press.

In one of a quasi-religous nature in January in the Idiofa-Kitwit region 450 miles east of Kinshasa, about 700 villagers were killed by the national guard sent in to quell it, according to local sources.

Other signs of unrest surfaced in March when 90 persons, including 67 military officers, were put on trial for allegedly plotting a coup against Mobutu. Then came the purge of Lunda and Luba officers from the army and a roundup of other suspected civilians from these two groups in Kinshasa.

Altogether, there were numerous signs that Mobutu held the Lundas in particular as increasingly dangerous to his authority even before the second Shaba war began two weeks ago.

It is not clear whether the Katangan rebels were planning their attack on Kolwezi in coordination with a Lunda and Luba revolt of officers from within the army. But clearly Mobutu believes there is a larger Lunda-led plot afoot aimed at bringing him down - the continuation of a political struggle under way in Zaire since Tshombe's demise and Mobutu's rise to power 13 years ago.

The main enemy, it appears from this, is not Cuba and the Soviet Union fomenting trouble from outside the country. Rather, Mobutu's troubles today have deep historical roots inside Zaire in the disaffection of one of its major tribes from the central government and the Lunda's quest for revenge and power.