There are plenty of personal reasons why Joe Biden has made this trip to the island of Ireland the longest of his visits as president but it is also just very good politics.
It is hugely important to him personally, no doubt.
He has said on this visit he is coming home. He feels that strongly. This is his ancestral and spiritual home.
“The best drop of blood in you is Irish,” he says he was told as a young man by his grandfather.
But he also knows the pictures we are seeing from Dublin, and later from County Mayo, play very well back home for a president who has just given his biggest hint yet that he will run for re-election.
At the heart of the president’s brand of politics has always been his decency, his supporters would no doubt argue.
His belief in dignity and duty appeals.
They are all values instilled in him, he says, by his Irish-American family.
And they are values that millions of Americans share and relate to.
Coming here and burnishing his credentials as a genuine son of Ireland strengthens that brand in the minds of voters in the US.
It reminds them why they liked Joe Biden in the first place and why – when it comes to it – they may want to return him to the White House, even in his 80s.