Amid the frustrations, Enda might recall Fine Gael's moment of 'Irexit' with the UK
When Enda Kenny was asked by a BBC reporter how he found Theresa May when they met at the end of last week, he answered: "Great fun". This was described as "gnomic", or evasive. Maybe the Taoiseach is right to be evasive, as you can't go into a poker game showing all your cards.
It is evident that the Government is, at best, extremely displeased, and at worst, absolutely furious, with Britain in general - and the Brexiteers in particular - for the decision to quit the EU. And understandably so - it has put Ireland in a difficult situation, and there will be many headaches over managing the Border between the North and south.
But I wonder if Enda ever casts his mind back to the decisions of his direct predecessor in Fine Gael, John A. Costello, who, in a reversal of the current situation, took the 26 counties - then called "Eire" - out of the Commonwealth back in 1948, to the exasperation and sometimes fury of the British (and the express "disappointment" of Australia).
Many Fine Gael voters - and especially Irish Protestants in the 26 counties - felt dismayed by this sudden break with Crown and Commonwealth. Senator David Norris remembered wistfully his Protestant relations in the Midlands feeling upset as they watched the officials of the newly declared Republic scrape the King's monographs off the letterboxes. (Not all the monographs were removed: with the passage of time, considerations for historical accuracy allowed some to remain - these post boxes being originally put there by the Royal Mail.)
Significantly, Éamon de Valera was opposed to Mr Costello's final break with the British link: he had rebuffed the British himself on many occasions (and locked antlers with Churchill during World War II), but he maintained that a residual Commonwealth connection would "build bridges" with Northern Ireland. And that the break engineered by the Fine Gael-led government would entrench Partition even more deeply. This proved to be the case, and hostilities across the Border were bitter in the 1950s.
All the fears being expressed by certain Irish people in Britain today about being treated as "aliens" once the UK exits from the EU were articulated, in almost identical form, by Irish emigrants to Britain in 1948-9, after the change in status. Now, Bob Geldof expresses similar worries that he might feel more of an alien as an Irishman in post-Brexit England. The British prime minister in 1948, Clement Attlee, was a socialist, but he was also a British patriot, and he considered putting in place administrative measures which would mean every Irish builder and every Irish nurse would have to register officially with the police on arriving in Britain.
He was prevailed upon not to do so - pragmatism came before offended pride in the end, as post-war Britain was greatly in need of those building workers and nurses - but he did respond decisively by giving a guarantee to Northern Ireland that its British status would never be altered, except by the consent of the people of the North. This, too, added another little measure of cement to harden the Border.
As Enda goes to bat to persuade Theresa May to negotiate a "soft" Brexit, and subsequently, as he goes to bat in Brussels to persuade the other Europeans that the British-Irish relationship is exceptional and special - in trade, culture and family ties (a quarter of English people have an Irish parent or grandparent) - will he cast his mind back to the times when the shoe was on the other foot? Will he ponder on the time when his political predecessor Mr Costello was leading an "Irexit" from a special relationship with Britain, and the British (especially the King, the mild-mannered George VI) were trying to work out a compromise?
Enda can lay some of the blame - if not most of the blame, by some historians' accounts - on Mr Costello's minister for foreign affairs (then called "external affairs") Seán MacBride, who is thought to have pushed the then-Taoiseach into declaring a Republic (at a Commonwealth conference in Canada, where, to worsen matters, Earl Alexander of Tunis, a dyed-in-the-wool Ulster Unionist, was said to have snubbed Mrs Costello).
MacBride, son of 1916 martyr John MacBride and Maud Gonne, was a passionate Republican and ardent Anglophobe. He fully subscribed to the Wolfe Tone doctrine: "Break the connection with England - the never-ending source of all our woes."
It's possible (and reasonable) that Ireland would have evolved towards a Republic anyway: this was the mission statement of 1916. But it was done in a very maladroit manner in 1948, which damaged British-Irish relations for some time, and it's piquant to note how history repeats itself - with an ironic twist.
Being a grown-up nation, like being a grown-up person, means taking responsibility for your actions and your history. Britain may have oppressed Ireland for 800 years - see some of the pitiful eviction scenes featured in the National Gallery's current exhibition Creating History - but over the past century, Ireland has often shown Anglophobic hostility. The IRA bombing of soft targets in England hasn't helped.
An Irish government chose to break the link with sterling, to join the Euro, to change the road signs from miles to kilometres. Perhaps these were sensible decisions in terms of EU commitment. Yet cumulatively, they added to further cleavages with the North - as De Valera feared - and more semi-detached relations with Britain.
This is the background to the newly found recognition that British-Irish relations are so special they need to be accorded exceptional treatment. We broke with Britain when it suited us, and now we want Prime Minister May to make arrangements that will stop the UK breaking further with us.
What goes around comes around. This is your moment, Enda, to make amends for that brusque rebuttal of British relations in 1948.