It is a meeting that could avert a clash of civilisations - conflict between Iran and America. If it goes ahead in the coming days, it would be a momentous and poignant encounter between two former presidents which could help Iran and the US overcome three decades of mutual hostility.
The former American president Jimmy Carter has agreed in principle to meet the former Iranian president Mohamed Khatami who arrives in the United States today.
US-Iran relations have been poisoned since the 1979 hostage-taking at the US embassy in Tehran, and that shadow would loom large in their meeting. Mr Carter has every reason to shun representatives of the Islamic Republic.
The 444-day hostage crisis was largely responsible for his electoral defeat by Ronald Reagan, months after a botched rescue attempt led to the deaths of eight servicemen in the Iranian desert.
On 20 January 1981, minutes after Mr Carter left office and Mr Reagan became President, the 52 hostages left Iran. Mr Khatami's Islamic regime has never repudiated the seizure.
The Washington Post quoted a former Carter aide as saying: "Carter, who has every reason to be angry about the way in which the Iranian revolution undid his presidency over the hostage affair, is willing to meet, with no hesitation, a person who was president of the Islamic republic and who has never disavowed Ayatollah Khomeini's actions when he was supreme leader."
The Carter Center, which focuses on human rights and building democracy, could not confirm that the meeting between the two former leaders had definitely been scheduled. The White House said Mr Khatami had been invited by private organisations and is not part of the Iranian government, which has been led by hardline President Mahmoud Ahmadinejad since last summer.
"Mr Khatami is free to meet with whom he chooses and is able to speak freely in the United States, the very freedoms that do not exist in Iran," a White House official said on condition of anonymity. "We expect that Khatami will face tough questions from his audience in the United States about the past and present behaviour of the Iranian regime, especially with respect to human rights violations that occurred during his presidency."
The US, which believes Iran to be intent on developing a nuclear weapon under cover of a civilian programme, has offered direct talks between the Bush administration and the Iranian government. But these talks, which would be the first in 27 years with the Islamic Republic, would only go ahead if Tehran accepts a UN-endorsed package of economic and technological incentives and resumes a freeze on sensitive nuclear activities by today.
But President Ahma-dinejad and Iran's supreme leader - who has the final say over Iran's nuclear programme - want negotiations on the Western offer and have rejected the UN's deadline for a freeze.
Individual UN Security Council members are reviewing Iran's 23-page response. Washington is expected to push for sanctions when the full 15-member council meets next week to discuss a response, after a reporttoday on Iranian compliance from the head of the UN nuclear watchdog, Mohamed ElBaradei.
The possible meeting between Mr Carter and Mr Khatami, during his two-week visit, could open an unofficial channel. While in the US, Mr Khatami is to speak at Washington's National Cathedral on 7 September. Before that, he will attend a closed-door UN conference on the "dialogue of civilisations" on 5 and 6 September, during which a high-level panel reviews a draft report for the UN secretary general.
A year ago, Kofi Annan set up the so-called Alliance of Civilisations sponsored by the Prime Ministers of Spain and Turkey, to overcome prejudice and misperception between Islamic and Western societies which has been exploited by extremists.
Archbishop Desmond Tutu of South Africa and the former Indonesian foreign minister, Ali Alatas, are among the 15 eminent personalities attending the UN meeting.
President Khatami, a reformer, sought to repair relations with the US and end Iran's isolation during his eight years in office. He called for a "dialogue of civilisations" in a speech to the UN General Assembly in September 1998.
During his trip, Mr Khatami may address the University of Virginia and an Islamic group in Chicago. He may also pay a private visit to Thomas Jefferson's home at Monticello, Virginia.
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