For Mrs Robinson is a bridge-builder, a peace-maker, and one who is poised to become one of the world's most influential leaders; she is widely tipped to unseat Boutros Boutros-Ghali and take over as United Nations' Secretary-General in January.
On the eve of her trip the Irish President chose her words with care in an interview with the Independent, acknowledging that there had been informal approaches about the UN post.
"I am not a candidate or seeking the position," she said. "I have made clear that my focus is on completing my term as President." But she left open the possibility of resignation. "I have a very strong commitment to human rights. I can't deny it. So, if it went to the wire about this position, I would have to weigh all the options which would be very difficult."
Mrs Robinson may be following the strategy of Javier Perez de Cuellar, who stayed out of the ring in 1981 until the incumbent, Kurt Waldheim, was vetoed. Mr de Cuellar emerged as the figure no one objected to. It may be for the same reason that Ireland wins the Eurovision Song Contest year after year, and that an Irish candidate would be similarly successful.
If Mrs Robinson is appointed over Mr Boutros-Ghali, who has become increasingly unpopular for being too aloof, antagonising the Americans and failing to overhaul the UN bureaucracy, she would be the first woman to hold one of the most important posts in world leadership - at a time of demand for figureheads who can strike a chord internationally. Many believe that her abilities as a moralist and as a leader place her in the same league as the Czech Republic's Vaclav Havel.
But, for all her skills, and for all the accolades, on this visit Mrs Robinson has been denied the chance of speaking to the joint Houses of Parliament. She will not be granted her wish to follow Jacques Chirac, the President of France, who addressed both Houses last month.
Officials deny any snub. But it seems the Government feared to allow the Irish head of state to address MPs during delicate negotiations for next week's all-party talks on Northern Ireland's future.
Ironically, this week's visit - including lunch with John Major tomorrow and with the Queen on Thursday - will highlight her diplomatic skills. Her predecessors had never visited Britain. George V was the last British monarch to take the boat the other way, travelling in 1913 to a troublesome corner of his then kingdom, soon to be plunged into the Easter Rising, civil war and separation from Britain.
Mrs Robinson, however, ushers in a new Irishness: proudly European, standing for diversity, pluralism and internationalism - all values that this radical, liberal, left-wing feminist holds dearest. It fits the long-standing efforts of the President, a Catholic married to a Protestant, to reach out to Ulster's Unionist community: she resigned from the Irish Labour Party in 1985, saying the Anglo-Irish Agreement was unfair to Unionists.
Two historical events - emigration and the Great Potato Famine of the 1840s - inform her revised national story. "Emigration," she said, "is no longer something with a finality that is sad. The experience helps us see Irishness as not simply territorial. It opens us to those in Northern Ireland whose sense of identity is more British than Irish." As for the famine: "It leads us to a strong identification with poverty, human rights and self-development."
All this goes down well with those, particularly Third World, countries that want her as Secretary-General. Sir Anthony Parsons, Britain's former Permanent Representative to the UN, confirmed that Mrs Robinson was a strong runner for the job. "The Irish have the advantage that none of the permanent members of the Security Council would probably veto their candidate," he said.
"Ireland is well respected. It has contributed to UN peace-keeping since 1956. It's neutral and has a close affinity to the Non-aligned Movement. There is a lot of stroppiness in the UN about the lack of women representatives in the UN secretariat.
"Mary Robinson is popular and has shown sound judgement, having helped bridge the gaps in Northern Ireland ... Politics in the Republic is a rough- and-tumble affair. But she has squared a lot of circles, rising above the all-male, Flaherty's-bar style of Irish politics. She has demonstrated independence while avoiding severe criticism. And being Irish is certainly a leg-up in the US."
In the coming months, Mrs Robinson has a chance to show her peace-making powers. As the beef war rages, the Republic, with its close affinity for Britain and enthusiasm for Europe, could play an important role. It takes over the rotating presidency of the European Union later this month.
"We will seek to be a bridge ... to minimise the difficult issues," Mrs Robinson said. "We would do this both for philosophical and also for bread- and-butter reasons. It would be good for Ireland if Britain were to have a more positive aspect and be benefiting more and contributing more to what is happening at the European level."
Looking further afield, she touched on a vital issue for the UN - civil war, the crucial form of conflict in an age when global war grows less likely and inter-state war is going out of fashion. "We haven't properly addressed the emerging democracies," she said.
"It is as though we think that, because they have opted for democracy, they have solved the problem."
Asked what the UN post should entail, she said: "There is a seeking for a global ethic. In a world that seems to have lost all spiritual cohesiveness, many people feel we need an ethical basis that values religions ... a secular tradition and is thoughtful about others."Reuse content