American president Obama, British prime minister Cameron and South African president ZumaThe agreement last month by Iran and the P5+1 to hold further negotiations in Baghdad today has inspired cautious optimism from many observers. But the real work still remains.

There has been no confirmed breakthrough beyond broad principles, and Iran has maintained its stance on preconditions (an outcome which elicited a torrent of triumphalism by conservative Iranian figures). All this could well signal a real gap in understanding between the two sides, rather than a coming together. The United States and its international partners must be prepared for a breakdown in talks even as they make the sincere effort to strike a deal with Iran. Developing a diplomatic plan B, employing a trusted intermediary able to bridge the confidence gap, could forestall further divisions and military conflict. South Africa could be an ideal backup go-between.

At talks in Istanbul, Iran showed it still has little trust in the West. Not only did the Iranian team insist that the venue of today's talks be in the capital of its Iraqi ally, but reports also claim Tehran refused bilateral meetings with all the P5+1 nations except China. As a willing and nontraditional mediator, South Africa would not face the Iranian skepticism the P5+1 historically has. It maintains the trust of Iran, and relations with Washington are on the mend. Having given up its own nuclear ambitions—still the only country to have done so after starting one from scratch—it brings unique credibility and perspective on the issue.

Outside intermediation has a checkered past, and there is reason to believe the authors of the failed 2009 “Tehran Declaration”—Brazil and Turkey—won’t play a role this time. Ties between Turkey and Iran have been increasingly strained, beginning with Turkey’s support for the NATO mission in Libya and its calls for Bashar al-Assad to step down, prompting many attempts by influential Iranian leaders to try to move talks away from Istanbul. At the same time, Brazilian president Dilma Rousseff has taken a stricter line on Iran than her predecessor, drawing the ire of Iranian officials. South Africa is one of the few potential intermediaries that Tehran still trusts.

Tehran’s Trust

Since the Islamic Republic’s support for the African National Congress during the apartheid era, Iran’s relations with South Africa have been strong. The bond is reinforced by South Africa’s dependence on Iranian crude oil, which makes up a quarter of its imports. Amid efforts by the United States to wean South Africa off Iranian oil, Tehran has moved decisively to shore up relations, announcing it will invest billions into South Africa’s beleaguered power-generation sector.

South Africa has tread lightly on the oil-sanctions issue—first agreeing to circumvent them, then suggesting it would look elsewhere for its supply. At the same time, oil-industry sources indicate Iran has rekindled talks about storing its excess production off South Africa’s cape coast, providing the regime with more options. Iran clearly values the flexibility an open relationship with South Africa affords it—despite South Africa’s conflicting signals.

To be sure, South Africa’s track record of brokering agreements is checkered. Its most successful mediation effort came over a decade ago in Burundi (2000), under former president Nelson Mandela’s stewardship. When Pretoria tried to intervene during the Iraq WMD standoff a few years later, its efforts ran aground amid a stronger war drumbeat. More recently, South Africa's flip-flops on the 2011 Libya crisis sent mixed messages: first supporting the UN Security Council resolution authorizing a no-fly zone, then mobilizing an abortive rearguard African Union mediation effort. With muted diplomatic failures in between in the Congo, Zimbabwe and Côte d’Ivoire, South Africa may see in the Iran standoff an opportunity to restore its international leadership. And though its diplomacy has tended to underleverage its corporate champions, there is evidence that South Africa is beginning to chart a more integrated approach to its ubuntu-style diplomacy, seeking to convert its economic might into political might. With substantial investments in Iran’s telecom and energy sectors, South Africa may also see diplomacy as a way of insulating its commercial interests.

America’s sanctions-focused approach could benefit from some further refinement, particularly in the case of South Africa. Even as they show real signs of impacting Iran’s economy, cast too wide, sanctions run the risk of unnecessarily complicating ties with an emerging leader. The impact of partially removing 5 percent of Iran’s crude exports would have a limited effect. A more tailored approach—going as far as including South Africa on the list of sanctions-exempted countries—would leverage Pretoria’s relations with Tehran and preserve it as a medium for private-channel approaches to engaging the regime.

An IAEA Role

A prominent South African role would also make use of Pretoria’s substantial influence in—and leadership of—the nonaligned movement (NAM), a group of nations generally less receptive to U.S. overtures with links to India and Brazil.

The nation has strong bonafides in nuclear diplomacy as well; South Africa’s special representative for disarmament, Abdul Minty, brings unparalleled institutional knowledge of the IAEA, having narrowly missing out in a heated succession battle to replace Mohamed El Baradei in 2009. Minty has sought confidence-building measures in the past, championing most recently a South African proposal to train several hundred Iranian nuclear scientists in reactor safety. He has drawn Washington’s ire on occasion, but this will give him more credibility in the Islamic Republic. His voice is a respected one among nonaligned nations and his forthright statements on Iran in the IAEA lend further credence to South Africa’s antiproliferation posture.

On the Mend

Despite an on-and-off relationship during the Mbeki-Bush era, relations between the United States and South Africa have improved. The country’s ambassadors have a strong working relationship, and the Obama administration’s ideological orientation sees more synergies with Pretoria than did its predecessor. There is also a strong recent history of partnering on nuclear safety issues. Unraveling the A.Q. Khan network—among the most successful partnered efforts against “loose nukes”—was the product of an effective joint strategy by South African, Israeli and American intelligence agencies. The current U.S.-South Africa Non-Proliferation and Disarmament Dialogue grew out of these partnerships and provides the basis on which to integrate South Africa into the Iranian negotiations.

Coming out of the crucial Baghdad meeting, Washington and its allies should work with Pretoria to reach out to Iran. South Africa should convey and defend the West’s goals and gain a truer sense of the Islamic Republic’s desires and concerns on the nuclear issue, sanctions and security needs—particularly in the event of a failure. U.S. policy makers are right to be optimistic. But with the stakes higher than ever, they should maintain a full arsenal of diplomatic tools. In a process in which trust has been sorely lacking, a supporting role for nations like South Africa could defuse a tense conflict—and prevent American blushes should the negotiations collapse yet again.