Hopes dim for S. Africa talks in 1986. Whites have hardened their opposition to compromise following a wave of attacks by blacks. Monday's arrest of activist Winnie Mandela underscores the toughening white stand.

1985 is going out with a sharp upturn in South Africa's civil war which has dampened hopes for black-white compromise in 1986. The recent wave of terrorist attacks, which claimed the lives of more than 10 white South Africans, has produced a bitter reaction among many whites.

Attitudes toward the African National Congress, which is held responsible for the attacks, have drastically hardened in the corridors of power. In the Cabinet, the hawks are rampant. The resolve on New Year's Eve is to fight the ANC ``murderers,'' even while pushing ahead with the government's very limited ``reform initiative.''

The government's harden-ing was underlined yesterday with the second arrest of black activist Winnie Mandela, wife of jailed ANC leader Nelson Mandela. Mrs. Mandela was arrested for defying a decree ordering her to stay out of her home township of Soweto. After her earlier arrest 10 days ago for disobeying the same order, she had been released with an order to appear in court Jan. 22. At press time Monday, the expectation was that she would be held in prison until that date.

Until the latest attacks -- including the Dec. 15 death of six whites in a landmine explosion near the border with Zimbabwe and the death six days later of five more whites in a bomb attack near Durban -- the prospect of negotiations between the government and the ANC was considered conceivable, if remote.

While President Pieter W. Botha adamantly insisted on rigid preconditions -- renunciation of violence by the ANC; expulsion of communists from its ranks; and the severing of ANC ties with the Soviet Union, its main supplier of arms -- there were important and influential forces in South African society in favor of talks.

They included businessmen and Afrikaner students and church leaders -- as manifest in the historic discussions in Zambia last September between leading businessmen and top ANC leaders and by later meetings between ANC officials and Afrikaner student leaders from the Univeristy of Stellenbosch (alma mater of all but one of South Africa's Afrikaner prime ministers) and between an ANC team and the rebel Dutch Reformed Church minister Nico Smith.

These contacts may have cleared the way for talks between government and ANC officials, the more so because, on the eve of the fatal landmine blast, there were unofficial discussions in New York between a top adviser to President Botha and a key member of the ANC's national executive committee.

But the government will press ahead in the new year with its ``reform initiative.'' Its objective is to draw ``moderate'' blacks over to its side and to build up a counterweight to the ANC. Statements by J. Chris Heunis, Minister of Constitutional Development and Planning and the man saddled with the responsibility of providing a place for blacks in South Africa's constitutional structure, make it clear that revival of the partly discredited black town councils remains a key priority.

To that end, Mr. Heunis, who has emerged as a serious contender to succeed Mr. Botha as president, has embarked on a program of recruiting black municipal police officers to help maintain ``law and order'' in the townships. Before June 1986, a 6,000-strong parapolice force will be operative in the black townships. They will provide a shield for the town councillors and, Heunis hopes, enhance their authority by providing them with political muscle in the turbulent townships.

On the national front, Mr. Botha is expected to initiate legislation to restore citizenship to more than 9 million black residents who were deprived of it when their designated ``homelands'' became supposedly independent states. It will be Mr. Heunis' task to devise a formula to give these blacks -- as well as the more than 7 million living in South Africa's still dependent ``homelands'' -- a share in the decisionmaking involving matters of national importance.

Next year will be critical for Mr. Heunis. So far he has declined to identify the black leaders he has been talking to but has hinted that the confidential discussions embrace leaders of substance. Publicly, however, no black leader of stature has admitted to talking with Heunis.

Chief Gatsha Buthelezi, leader of the 1.1 million-strong Inkatha Movement, is seen by many whites as indispensable to the success of any ``internal settlement'' that excludes the ANC. But he has refused to negotiate a deal with Mr. Botha -- and therefore with Mr. Huenis -- until the state of emergency is lifted and Botha commits himself unequivocably to negotiating a power-sharing constitution for South Africans of both races.

There will be ongoing piecemeal reform. But, according to well-placed sources, the government is likely to stall on the recommendation by the President's Council that it abolish its influx control laws, which pen millions of blacks up in poverty-stricken rural areas, and replace it with a policy of ``orderly urbanization.''

Meanwhile, the ANC remains firmly committed to intensifying the ``armed struggle.'' Its aim is to continue the switch in strategy away from limited attacks by well-trained, largely externally based guerrillas to a ``people's war'' launched from within by a ``people's militia.''

But as the ``people's war'' takes off, the externally-based ANC high command risks losing control of its troops. It is speculated that the bomb that killed five whites before Christmas may have been the work of an ill-disciplined people's unit permanently inside South Africa. The conjecture is that the group was angered by the Dec. 20 assassination of six ANC cadres in Lesotho by men suspected of being South African Army commanders.

Less well-trained guerrillas are increasingly likely to opt for ``soft'' civilian targets instead of ``hard'' military installations. Whatever the long-term results of terrorist attacks on civilians, their short-term effect will be to strengthen the white community's hawkish attitude.

The prognosis for 1986 is hardly sanguine. The course of events is set for polarization, as the dominant whites drive to recruit ``moderate'' blacks while black nationalists continue their ``war of resistance'' against the evolving system of neo-apartheid and its black ``collaborators.''