Mr de Klerk said that his decision to quit the NP, the Afrikaner-dominated party which enforced apartheid during a four-decade rule, was a sacrifice for the party's future.
He said the "unjustified perception" that the NP was still linked to a guilt-ridden past was obstructing political realignment in the country. "The last remaining high-profile link with the old NP and its so-called baggage withdraws himself from the active party-political scene," said Mr de Klerk yesterday in Cape Town.
His withdrawal may prove a useless gesture. For even if the political reinvention was possible - and that is very doubtful - Mr de Klerk is leaving a party at war with itself; ripped apart by conservative die-hards who argue too much of Afrikanerdom has already been conceded in the negotiated transition to black majority rule and reformers who insist the NP must transform itself into a black-led, multi-racial mass movement to survive.
Yesterday Mr de Klerk claimed there had been no internal pressure on him to resign.
But for months, the man who stunned the world in 1990 by unbanning the ANC, releasing Nelson Mandela and entering into negotiations to end white minority rule, has struggled to create a viable opposition to the ANC, all the time torn between his left and right wings.
In the end he failed to please either. Yesterday the right-wingers were the most vocal. General Constand Viljoen, of the right-wing Freedom Front, said Mr de Klerk 's departure was a positive development in Afrikaner politics, while a Boerestaat Party spokesman said Mr de Klerk's "treachery towards his people was unequalled." The past eight months have been particularly tough for Mr de Klerk . The extent of right-wing discontent became evident earlier this year when Die Burger, a conservative Afrikaans newspaper, launched an unprecedented attack on Mr de Klerk 's leadership. It appears to have weakened Mr de Klerk 's support for the party's reformers.
Three months ago Roelf Meyer, a reformer who won acclaim as the NP's chief negotiator during the peace talks, resigned to start a new political movement.
Mr Meyer left after the NP reform think-tank he headed was axed under pressure from the right. A haemorrhage of reformist NP members has followed and Mr Meyer's new party will be launched next month.
Since Mr Meyer's departure the NP's fortunes have continued to decline. Mr de Klerk's resignation comes a week after a new survey showed NP support has slumped to 12 per cent, compared to 21 per cent in the 1994 elections.
White desertion of the political process is largely responsible. Research also suggests the party has actually lost the little black support it had.
Only in the Western Cape, dominated by NP-supporting Coloured (mixed- race) voters, does the NP have political control; leading to predictions that it will soon become just a regional force, holed up in the only province it controls.
"The NP is a sinking ship," said Theo Bekker, political science lecturer at Pretoria University. He argues there is no one to take Mr de Klerk 's place.
Neither front-runner - Marthinus van Schalwyk, one of the reformers who remain, and Hernus Kriel, Western Cape premier and darling of the right - have the stature necessary to prevent further splintering.
Yesterday political commentators said Mr de Klerk, 61, should have got out while his reputation was intact. For the last year has been as damaging to him as his party.
Mr de Klerk undoubtedly deserved the international acclaim - and the 1993 Nobel Peace Prize he shared with President Nelson Mandela - for his dramatic decision to enter into negotiations with the ANC.
It went against everything he, as a member of the elite Afrikaner conservative establishment, seemed to stand for and came just a year after he ousted the ailing PW Botha from power. But recent concessions to his right wing have sullied his reformist credentials.
And his reputation has been further damaged by the apartheid-era atrocities exposed by the Truth and Reconciliation Commission, the independent body charged with exposing the truth about South Africa's past.
In May Mr de Klerk 's failure to disclose all he is assumed to know about the NP's sins to a special TRC hearing - and his refusal to accept responsibility on behalf of his party for apartheid-era human-rights abuses - almost reduced Archbishop Desmond Tutu, TRC chairman, to tears.
His performance also won him almost universal criticism in the international and national press. One newspaper described Mr de Klerk as SA's very own Rip Van Winkle; a political leader who chaired the country's Security Council but somehow managed to sleep through all the violence it sanctioned.
The debate about just what Mr de Klerk will be remembered for will rage for years. But yesterday some, at least, were generous.
Stanley Magoba, leader of the Pan Africanist Congress, said Mr de Klerk had at least been an NP leader willing to listen. "I used to see him as a living example of dialogue, as opposed to PW Botha's monologue."
President Mandela's regard for Mr de Klerk has apparently plummeted since 1994.
But yesterday he said that, personal shortcomings apart, South Africa should not forget Mr de Klerk 's contribution in smoothing the transition from "our painful past."
Tony Leon, of the Democratic Party, went further. "Mr de Klerk will be much better judged by history than by his critics and opponents now," he said.