Obama still has key role on North
In 1892 William Butler Yeats, in his masterful poem 'The Lake Isle of Innisfree', noted "peace comes dropping slow" -- and that was 106 years before the Good Friday Agreement.
In 1992, when William Jefferson Clinton was elected president of the United States, he fast-forwarded Yeats' notion and six years later a peace formula was finally agreed in Northern Ireland.
And for all the hitches and maddening nitpicking, the agreement has now prevailed for more than 13 years against all the odds.
Barack Obama will be saluting his presidential predecessors as the progenitors of the struggle for peace and the deliverance of relative prosperity in Northern Ireland.
And no reasonable person could deny that the input of the United States was vital to have the Good Friday Agreement accepted by both communities.
While President Clinton has got all the credit for the US's involvement, the efforts of his successor George W Bush have been either forgotten or ignored.
George W Bush, the 43rd US president, was asked by Bill Clinton in 2006 to use all the powers of his office to sell the St Andrew's Agreement to Rev Ian Paisley.
President Bush, a born-again Christian, didn't hesitate and persuaded a doubting DUP and the founder of the Free Presbyterian Church.
Former US presidents are members of the most exclusive club in the world and two of its four members have been deeply involved in Northern Ireland.
President Obama has promised to continue US involvement and committed huge resources to supporting Northern Ireland, both politically and economically.
The recent upsurge of republican dissidents and their murderous campaign are a threat but the US has been unequivocal in its denunciation of them.
The US has had a presence in Northern Ireland for 211 years, since the first US Consulate opened in Belfast in 1796.
But then more than one-third of all US presidents -- 12 to date -- have direct roots back to Northern Ireland, all of them from Protestant backgrounds.
With so many past presidents having direct links back to Northern Ireland, and a consular presence in Belfast for more than 200 years, US involvement there is not so surprising.
But the United States has been a true friend to Ireland, North and South, and has invested prestige, time and money in the project.