The enemies the South African president had in mind were Cuba, Iran and Libya. On two out of the three counts it appears that Mr Clinton was lending an ear. While he politely opted not to rise to Mr Mandela's public challenge, his national security adviser, Sandy Berger, did. Responding on Mr Clinton's behalf, Mr Berger tellingly omitted Cuba and Iran, noting only that, "based on principle", the US could not possibly establish relations with Libya.
Lockerbie remains an issue but, as Mr Berger might have added had he been more candid, the Bay of Pigs fiasco and the embassy hostage-taking in Tehran are acquiring something of the musty irrelevance of Ulster's Battle of the Boyne. The signs are that the US is beginning finally to contemplate the prospect of rapprochement with two countries long identified by Washington as incurably hostile rogue states.
The most recent signs came from the Pentagon, of all places. On Thursday a Pentagon spokesman bluntly rejected a report emanating from Israel that Iran had acquired several nuclear warheads from a former Soviet republic. "We have no evidence whatsoever that that is the case," said Defence Department spokesman Kenneth Bacon.
That day Fidel Castro praised as "objective" and "serious" a recent Pentagon report that said the Cuban military no longer represented a threat to its neighbours. In an unprecedented effusion of love for "el To Sam", the Comandante also welcomed as "positive" Washington's decision three weeks ago to ease the 37-year-old embargo against Cuba.
In what appears to have been a reponse to calls in January by Pope John Paul and, no less significant, American big business, for the US embargo to be lifted, the White House announced on 20 March measures designed to ease restrictions on travel and humanitarian aid to Cuba.
A further indication that the US is testing the waters off the south coast of Florida was provided on Monday after a meeting between Madeleine Albright, the Secretary of State, and Basdeo Panday, Prime Minister of Trinidad and Tobago. Mr Panday, a close American ally, emerged from the meeting to announce at a press conference that he detected a softening of US attitudes towards Cuba, though these were being constrained by right- wing Cuban exiles and their congressional confreres.
Also discussed at the meeting were plans to admit Cuba into the 15-member Caribbean Community (Caricom). Traditionally the US has objected to close economic and political links between Cuba and its neighbours, but Ms Albright meekly told a press conference that the US would not try to influence Caricom's decision on whether to admit Cuba or not.
These are all subtle indicators of a shift in US policy towards Cuba. In political terms the Clinton administration would have no problem changing tack once again in the event of provocation from Dr Castro or pressure from Senator Jesse Helms. Less subtle, however, is the blunt truth that the rationale for imposing the embargo on Cuba no longer exists.
As Mark Alcoff, a conservative Cuba expert at the American Enterprise Institute has recently pointed out, this rationale was based on two objectives. "To force the Soviet Union to spend money to prop him up, and to make it more expensive for him to foment revolution in the rest of Latin America."
The fact is that today Cuba, long deprived of its massive Soviet oil subsidies, has been exposed as a small, impoverished Third World nation engaging in an experiment which neither Latin America nor anywhere else has any desire to emulate.
It is otherwise with Iran, whose oil wealth and strategic geopolitical location makes it a nation which the US has more reason to fear, but also more reason to be friends with. And while it is less less logically inevitable than with Cuba that the barriers will fall, the indications that the US wishes to explore a warmer relationship with Iran are, if anything, louder and more distinct.
In a clear echo of the ping-pong diplomacy the US and China practised a quarter of a century ago, a team of Iranian wrestlers competed against American wrestlers at the sport's 1998 World Cup championships in Oklahoma last weekend. The American fans welcomed the Iranians rapturously, as had the Iranian fans when the US team visited Tehran in February.
Mr Clinton, ever attuned to grassroots American sentiment, invited the US team to the White House after their return from Tehran, in what was pointedly intended as a cordial response to an invitation in March by Iran's new reformist president, Mohammad Khatami, for a "dialogue of civilisations" between the US and Iran.
Beyond the symbolism, Newt Gingrich, the Republican speaker of the House of Representatives, met the Iranian Foreign Minister, Kamal Kharrazi, in Switzerland in February. On his return to Washington, Mr Gingrich told the White House that he believed the US could "do business" with Iran's new government.
Mr Gingrich is no solitary voice on Capitol Hill. A group of Republican members of Congress asked Ms Albright last week to ease visa restrictions on Iranians "to help foster people-to-people exchanges that would help move us closer to the authorative government-to-government dialogue we seek".
There have been other initiatives suggesting a thaw in relations between the mullahs and the Great Satan. The State Department recently permitted Iran's ambassador to the UN to attend a conference on the future of the US-Iranian relationship in California, waiving a rule that requires him to stray no further than 25 miles from New York City. The State Department is also reported to be discussing plans for reciprocal visits by academics, lawyers and artists.Reuse content