A generation of American activists was inspired by the struggle against apartheid in South Africa, which promised moral clarity amid the cruel compromises of the cold war. As Barack Obama vividly explained in Dreams from My Father, he was one of them. Given the foreign policy dilemmas that the president will face in the years ahead, it's worth thinking through the lessons of the South African transition.

With the possible exception of the fall of fascism in Germany and Japan, the South African experiment represents the most successful transition from authoritarianism the world has yet seen. And as South Africans will ceaselessly remind you, there was nothing inevitable about this success, particularly in light of the massive economic inequality and enduring racial resentment that are the legacy of apartheid.

While in exile, the African National Congress made many friends and allies among left-of-center parties and intellectuals in the West and Marxist and radical governments throughout the world. The international dimension of the liberation struggle was vitally important, and the ANC was careful to manage its image, projecting fiery radicalism and sober moderation, depending on circumstance and audience. Conservatives tended to dismiss the ANC as a band of unreconstructed communists and terrorists, but the truth was that, as at least some of its left-wing allies understood, it was a broad-based movement that reflected the fractiousness, diversity and contradictions of the South Africa's dispossessed majority. To be sure, the ANC was riddled with informers and scoundrels of all kinds, at least a few of whom have gone on to become spectacularly corrupt. But it also included principled, selfless leaders and a not inconsiderable number of revolutionaries who later became talented technocrats.

Apartheid-era South Africa was in this regard far more fortunate than Iraq, where the democratic opposition had been sapped and weakened by the ruthlessness Saddam Hussein, or Iran, where the quasi-democratic nature of the state has divided and conquered advocates of a more tolerant and humane government. The ANC had a long and storied history before it was banned by the apartheid regime, and it was a multiracial, multi-ethnic movement from the start.

It was a far cry from the Iraqi National Congress of Ahmad Chalabi, which seemed faintly comic in comparison. Indeed, one wonders about the counterfactual in which Iraq had its own ANC, an organization with the legitimacy to make demands on behalf of oppressed Iraqis. Perhaps this would have been a movement of the left, one that would forthrightly condemn efforts by the United States to overthrow the Baathists as an imperialist power-grab. Or it might have been friendly to the prospect of an American intervention, and fully capable of fighting alongside coalition forces.

Iran's exiles, many of them deeply committed to the overthrow of the mullahs, come across as deeply unrepresentative, drawn as they are from the most educated and affluent stratum of Iran's population. Like Saddam, the Iranian regime has succeeded in disrupting links between exiles and inziles, internal opponents who could gather intelligence and command legitimacy in a moment of crisis--not unlike the post-election crisis that has unfolded over the past few weeks.

One of the more striking ironies of apartheid South Africa is that it was a state with the most obscene laws, yet it claimed to adhere rigorously to those laws. Torture was extremely pervasive, but the National Party insisted that it adhered to constitutional norms. And so the enemies of the regime were able to use the language of human rights and democracy against it to devastating effect. In a few instances, brutal criminals operating under the auspices of the state's "counter-insurgency" unit were imprisoned long before the transition. Just as Gandhi had a suitable foe in the legalistic British, who, lest we forget, employed vicious violence against the independence movement, the National Party couldn't fight Nelson Mandela without digging its own grave.

After the democratic transition, the ANC stunned its detractors by building a truly representative government, one that was incredibly keen, occasional corruption notwithstanding, on sober macroeconomic management. The government is now undertaking a massive campaign of infrastructure improvements, financed with a deficit far smaller than those now seen in the United States and Britain. Tax revenues increased mightily in the years since 1994 as Afrikaner socialism has been carefully unraveled. Which leads us to one of the more peculiar lessons of the South African experience.

During apartheid, the ANC strongly championed the divestment movement and efforts to impose sanctions and otherwise economically isolate South Africa. Because the National Party ultimately cracked, many now believe that the sanctions played a vital role. And yet it turns out that economic isolation mainly had the effect of distorting the shape of the South African economy, driving up wages for those in the formal sector, creating an overlarge financial sector and concentrating economic power in the hands of a small number of firms.

To build the apartheid state, the National Party vociferously rejected economic liberalism, which would have undermined its racial hierarchies by, among other things, creating insatiable demand for the labor of the majority population. The end of the sanctions regime clearly benefited the South African economy. The more significant gains in growth, however, have come from the dismantling of so-called import-substitution industrialization, an idea the ruling Afrikaners embraced with the gusto of Latin American Marxists long before international sanctions.

In a sense, sanctions represented the moral outrage of the international community. No one intended to invade South Africa to overthrow apartheid, and economic isolation seemed like the next best thing. Of course, the success of the post-apartheid settlement rests in large part on the fact that it was ultimately an internal settlement.

Had foreigners been deeply involved--had Secretary of State James Baker shuttled in to Pretoria to hammer out the final negotiations, as I'm sure he dearly wished--it would have been easy for one or both parties to say the deal was null and void, as it had been the product of external coercion. But instead it was committed cadres of the National Party and the African National Congress who decided, on their own terms, to retreat from the brink of disaster.

So what can President Obama, and we as citizens of the world's most powerful country, learn from South Africa, particularly when it comes to encouraging democratic transitions? The news is rather grim, unfortunately. The forces that back reform have to be seen as authentic and deeply rooted in their societies. Short-circuiting this process through external intervention can backfire very badly.

Since Iran's disputed election, I've felt very strongly that Americans should defend the right of Iranians to protest against their government, and I've also felt that the Iranian crackdown reveals the moral hollowness of the Iranian state's democratic pretensions. And in this column, I've urged the president to build an international coalition that could use economic coercion against the Iranian elite to break its will.

But what the South African example tells us is that none of this will matter unless the Iranian opposition can build a broad-based, effective, shrewd political movement that reflects the diversity and the interests of all Iranians, one that can operate inside and outside the country and defend itself against the secret police. This won't happen overnight.

Serious observers are convinced that the Iranian regime is quite robust, and that it can disturb a few protests and a few riots. That means that Iranians will need leaders with all the patience, fortitude and intelligence of Mandela on Robben Island.

I've spent the past week on an international media tour sponsored by the government-backed organization Brand South Africa. Despite the unusually grim weather, very rare in these parts, this has without a doubt contributed to my pre-existing positive feelings about the country, so please take my praise with a grain of salt.