Leading Article: South Africa's moment of truth

The South African government of national unity is no more. The National Party, the pillar of white rule, has finally left government. But the country has gained a constitution, and an opposition committed to working within it. The National Party has willingly and peacefully relinquished what remained of its hold on power. A decade ago that seemed inconceivable. That it has happened is a tribute to the new South Africa and its emerging political maturity. The party's departure was a shock. There are risks for the ANC in going it alone in government. Yet there are also great opportunities and grounds for cautious optimism for South Africa.

Just the day after Parliament endorsed the new constitution, FW de Klerk and his National Party announced their withdrawal from the coalition led by President Mandela. Sooner or later the collapse of the coalition was inevitable. A long-term governing partnership between the party that first established and then presided over decades of apartheid rule and the movement that fought it and suffered under it for so long was never a plausible proposition. After the country's first elections, in 1994, delivered an overwhelming majority to the ANC, the only question was when, not if, black majority rule would commence.

But it is a tribute to both Mandela and de Klerk that they have held the coalition together for so long. The National Party's role in the transition government was essential. It helped the white minority to accept the ANC's accession to power, and steadied the markets while the newcomers gained experience in government. Now the party has conferred legitimacy on the new constitution.

De Klerk deserves personal recognition. He is a leader who has done the very hardest thing: he has known when to give up power and to force his party and his people to change. His role as been essential to the maintenance of peace in the country. Now is as good a time as any for de Klerk and Mandela to go their separate ways. The negotiations over the constitution were fraught, and many details as a result remain fudged. The National Party was desperate to protect property rights. They have had to accept merely that expropriation won't take place without compensation. Other tensions remain over Afrikaner schools, union rights and the death penalty. It had become blatantly clear to everyone that the National Party was reconsidering its membership of the coalition. The resultant uncertainty and speculation in the financial markets meant that de Klerk was right to make his announcement now.

The emergence of a genuine majority government faced with a vocal and sensible opposition should be grounds for optimism. De Klerk sounded peeved yesterday when he said: "The ANC is acting more and more as if they no longer need a multi-party government

Of course there are risks, not least in the racial nature of the political divide. In a truly multiracial South Africa, every issue and every interest should not be divided and articulated along racial lines. This is a chance for the National Party to establish itself as more than a whites' party. It needs to develop itself as an ideological and conservative force that appeals across races and classes. For its part, the ANC will need to find other ways to keep control of its extremists, now that it can no longer use the National Party as a counterweight.

While the establishment of a democratic opposition is welcome, other important political and constitutional developments have yet to take place. Inkatha's position remains strained. It has distanced itself from the government, although Chief Buthelezi remains in the cabinet. The ANC and the trade unions still need to resolve the complicated nature of their relationship. And the party itself needs to develop an effective internal structure that does not depend on the personality of Nelson Mandela to hold it together.

The National Party's departure could open a new era of more mature party politics. It may trigger a crisis. The future is in the hands of the ANC. Its moment has finally come.