BARACK OBAMA is one of the greatest orators of the present age. He can move vast audiences to enthusiasm or tears -- or both. Tonight he will surely enchant listeners at his rally in one of Dublin's most historic locations, College Green.
The US president's task is much easier than that of Queen Elizabeth last week. Hers was no less than to copperfasten a happy, free and equal relationship between Ireland and Britain. She succeeded beyond the dreams of any past generation. While doing so, she attracted overwhelming admiration for her personal qualities.
Mr Obama, by contrast, follows a long line of American leaders who celebrated their Irish descent on their visits to this country. Our two outstanding relationships were with John F Kennedy and Bill Clinton -- the first because we took pride in Irish successes in the United States; the second for his hard work on the Northern peace process.
The present incumbent is, from the Irish viewpoint, something of an unknown quantity. That may seem extraordinary when one speaks of a man whose every word, every gesture is examined for world significance. But he is not instantly "knowable" in the way of a Kennedy or a Clinton.
His connections with Ireland are not of the folksy kind. Although his political career had its beginnings in Chicago and owed something to his friendship with an Irish-American dynasty, that does not compare -- and he would hardly wish it to compare -- with Kennedy's family and political roots in Boston.
If one seeks an Irish influence, it is to be found not in any American city but here at home.
The first black US president has an enormous admiration for Abraham Lincoln, probably the greatest among all the holders of the office. Lincoln freed the slaves and held his country together at the cost of a terrible civil war. Long before that war the greatest Irishman, Daniel O'Connell, supported the cause of what was quaintly called "negro emancipation". As well he might, since he himself had brought about Catholic emancipation.
That is a connection of which we all can be, and should be, proud. In the intertwined histories of Ireland, Britain and the US, there is much that we may, like Queen Elizabeth, wish had been done differently "or not at all", but the cause of human rights is indivisible.
When Canon Stephen Neill traced Mr Obama's Irish descent to the little village of Moneygall, few of us thought of Abraham Lincoln or Daniel O'Connell. We regarded it more as a curiosity than a matter of moment. But it prompted some of us to take a more intense interest in the president's career. And it may have caused us to view the United States with even more affection than usual.
We had long seen the country as a refuge, then as a place where refugees from extreme poverty grew immensely rich. Next we saw it as a saviour, in wartime and postwar Europe -- and as the abundant source of the investment which made us rich for a while and can make us rich again.
We lamented American tragedies: the terrorist destruction of the Twin Towers; the inundation of New Orleans. In recent years, we have grown more critical. The administration of President George W Bush was deeply unpopular in Europe. A great many, here as elsewhere, greeted the advent of a new regime with joy.
But the new president inherited gigantic domestic and foreign difficulties and has had to struggle to keep them at bay. On his European trip, he intends to revive efforts to address one of the most intractable and threatening problems of all -- the Middle East question.
It might be thought that the Irish visit amounts only to a moment of ease, and strong hints have been dropped to that effect. In reality, we not only have enormous internal problems, we have important bilateral issues that need to be addressed at the highest level. In addition, the involvement of US Treasury Secretary Timothy Geithner in events surrounding Ireland's EU-IMF bailout reminds us that our economic meltdown has implications not merely for ourselves and Europe but for the world financial system.
We will give Mr Obama as warm an Irish welcome as we gave Queen Elizabeth; we will not forget American generosity. But all relationships flow both ways, and we have some questions to raise.