Pyrrhic Victory for S. Africa's Botha? After public battle, President seems set to stay on - without his party's backing. POWER STRUGGLE

HOPING to avoid a head on confrontation, South Africa's ruling National Party apparently is backing down on its demand that President Pieter Botha resign. This seeming resolution comes after weeks of a rather Byzantine power struggle played out in the press here. It pitted a defiant Mr. Botha - who stepped down as party chief in January after a stroke - against an equally adamant Frederik de Klerk, the new National Party leader.

At issue was Botha's desire to stay on as President past the next election (due by March 1990), while relegating the daily running of the country to Mr. De Klerk. But backed by a party caucus that reportedly was fed up with Botha's somewhat heavy-handed governing style, De Klerk refused to play ball.

Thus, the highly publicized battle that - at least on the face of it - Botha seems to have won. But many political analysts see it as a Pyrrhic victory. Without a unified government, they say, significant reforms to the country's segregationist apartheid system will be almost impossible.

``This is going to be a lame-duck administration in the classic American sense,'' warns David Welsh, a University of Cape Town political scientist. ``I can't foresee any major breakthroughs as long as Botha rules without the backing of his party.''

The President's problems started after his resignation as party chief. Conventional wisdom had it that he would step down from the presidency and make way for De Klerk to call a new election. But Botha remained silent about the matter. So the usually pro-government newspapers started running stories about the ``dilemma'' Botha was creating by not defining the division of power between himself and De Klerk.

The admonishments and speculation continued until last Sunday, when Botha made clear in a nationally televised interview that he had no intention of resigning. In fact, he announced he was returning to work Wednesday, two weeks earlier than expected. Botha also said there would no election this year.

BOTHA wants to stick around, a government official said in an interview, because he wants to go down in history as the man who brought disenfranchised blacks into national government. To free himself to concentrate on the plan, Botha came up with a scheme which called for De Klerk to be named prime minister.

An election then would be called in which the Nationals would put up Botha for president - an unprecedented move, since the party leader always has received the nomination. In exchange, Botha would stay on for about a year, then pass De Klerk the presidency.

However, few in the party backed the plan - or Botha's decision not to resign. His interview caused a huge brouhaha, with Nationalists convening meetings of their Federal Council - their highest advisory board - and caucus last Monday to try to decide what to do.

But despite the uproar, the decisions carried considerably less punch than expected. Nationalists agreed that while they wanted to again merge the posts of party chief and president, special provisions would be made for Botha to finish out his term.

``There's little the Nationals could do,'' explains political scientist Welsh. ``They could try to impeach Botha, but that would have ripped the party apart.''

While the Nationals' acquiescence may have prevented a damaging party brawl, Sampie Terre Blanche says it hasn't done much for the nation. ``Now Botha can try to make his mark in history,'' says Mr. Terre Blanche, a Stellenbosch University economist. ``But if he doesn't have backing, how can he deliver?''