Black states' support for ANC wilts under S. African pressure

The group that has battled for 72 years to build black political resistance to white-minority rule in South Africa - the African National Congress - could be at a crucial juncture, analysts say.

Support for the ANC from black states bordering South Africa is wilting under immense pressure from Pretoria. Mozambique, the last and most important exception to this pattern, appears ready for some form of -''nonaggres- sion'' pact, perhaps more tacit than formal, with South Africa.

This laying out of the ''unwelcome'' mat by the region's black governments, even if reluctantly, leaves the ANC with some tough decisions, analysts say.

Most analysts believe the ANC could continue its sabotage attacks, either from within South Africa or through the long and permeable borders South Africa shares with its neighbors. But Pretoria has clearly raised the stakes for the ANC in pursuing such a tactic: Further ANC raids may bring the wrath of Pretoria down on neighboring states, whether or not they are directly responsible. Thus relations between the black governments and the ANC are further strained.

Another option apparently open to the ANC is to shift gears, downgrading sabotage activity and concentrating on further strengthening of its underground political support within South Africa.

The difficulty with this course is that the ANC is banned in South Africa and has effectively used sabotage not so much to physically weaken white rule, but to ''excite admiration'' among blacks, says Tom Lodge of the University of the Witwatersrand in Johannesburg.

Mr. Lodge, who has studied the ANC, says the sabotage campaign has yielded political benefits and made the group the ''center of political gravity'' in South Africa's black townships. But as an outlawed organization, working solely on the political level will be difficult, Lodge points out. Mozambique's apparent willingness to reduce support for the ANC to the strictly diplomatic and rhetorical level marks a turning point for the ANC.

The ANC was banned in 1960, but a popular revival began in '75, Lodge says.

It was in 1975 that Portugal's rule in Mozambique and Angola was -over- thrown. ANC links with rebels who gained power in those countries paid off. Lodge says support of the new Mozambican and Angolan rulers ''was fundamental in the launching of an insurgency in South Africa.''

Since 1975, the ANC's sabotage campaign has escalated steadily with Mozambique apparently serving as the primary staging point for the attacks and Angola serving as a training center. Lodge says it is unclear whether the Mozambique government has actively aided the ANC. But evidence suggests that ANC rebels have been ''funneled through Mozambique'' and that Maputo has turned a blind eye, he says.

Since 1981, South Africa has launched three strikes against alleged ANC nests in Mozambique to pressure Maputo into restraining the ANC. The tactic and alleged Pretoria support for Mozambican rebels appear to have paid off - as they apparently have in Swaziland and Lesotho, which South Africa also pressured.

South Africa and Mozambique have held talks focusing on security issues, but extending to economic relations.

They apparently accepted in principle the idea of cooperating on security, with the Mozambicans restraining the ANC and Pretoria restraining the Mozambican rebels. Analysts consider the rapprochement ''fragile.'' Zimbabwe and Botswana also refuse to let the ANC operate militarily on their soil.