It all seemed to be going so well. The North South Ministerial Council on July 31 (the first plenary session in almost four years) had been civil and useful, with both sides pleased about progress on the response to Covid-19, New Decade, New Approach commitments and dealing with the implications of the UK's withdrawal from the EU in a few months' time.
There wasn't a peep from Micheal Martin about the Shared Ireland Unit (SIU) in the Irish Government's Programme for Government, leading Arlene Foster to say: "It does not threaten our constitutional position, or what we believe in, so I don't feel threatened at all by the unit."
The day ended - as all these events are meant to end - with smiles, a socially-distanced photo opportunity, a promise to see you all soon and a fairly bland joint communiqué.
But a week later, in an interview with the Irish Independent, the Taoiseach announced that he planned to "beef up" the SIU because "there are two distinct political jurisdictions born out of the Good Friday Agreement and we have to acknowledge the reality of that".
Had he stopped at that point it would probably have been okay; for at that point it was just a vague indication that he was minded to do something. Politicians say things like that all the time in interviews knowing full well it's flannel. But Micheal Martin went further. Much, much further.
He noted the importance of English nationalism to the Brexit vote and suggested that Scotland could maybe opt for independence.
Then he added: "(But) what happens if England gets turned off Northern Ireland? We've got to be thinking all this through."
Are we to conclude, therefore, that beefing up the SIU indicates his willingness to begin the preparation for Irish unity?
And, if so, does he intend to include unionism in this "beefing-up" process?
He didn't, as far as I know, text, tweet, email, call or Zoom Arlene to let her know what he had said. Even an "it's for the local optics" message would have dampened concerns at her end.
But his failure to do any of that suggests he is serious. If so he is putting himself firmly in the Sinn Fein camp (which maybe he thinks he needs to after recent opinion polls show Fianna Fail falling further behind Mary Lou McDonald).
It may also mean that the SDLP's recently launched New Ireland Commission (within which Colum Eastwood hopes to engage "political unionism"), which Micheal Martin would almost certainly have given an imprimatur to, is an integral part of the "beefing-up" strategy.
More importantly, Micheal Martin would have been well aware that his comments would annoy the hell out of unionist leaders, most of whom welcomed his elevation to Taoiseach.
Their relationship with Leo Varadkar had been, for most of the time, fairly tetchy, with even the Brexit sceptics worried that he was playing the "England's misfortune is Ireland's opportunity" card too eagerly.
Most of them viewed Micheal Martin in a more benign light, believing that he wasn't keen on adding to his in-tray problems by going out of his way to irritate unionism at an already anxious time for them.
Crucially, Micheal Martin knows that there cannot be a united Ireland without majority endorsement in a border poll and he knows that the poll requires the approval of the British Government.
So, when he suggests that England could get "turned off" Northern Ireland, is he further suggesting that the Government would push for a border poll?
It's an important question, because while Arlene Foster was correct to respond to him that "the principle of consent determines Northern Ireland's place in the UK", is Micheal Martin also correct to hint that a combination of English nationalism, Scottish independence and a PM who seems, at best, disinterested in Northern Ireland would be the ultimate determining factor?
At the heart of Foster's response to Micheal Martin is the argument that the rest of the UK cannot "sever" its constitutional links to Northern Ireland.
Yet, the very Prime Minster in whom she placed so much faith didn't so much as blink when he let her down over his "no border in the Irish Sea" pledge.
Hand on heart, how far does she, or any other unionist for that matter, trust Boris Johnson to prioritise Northern Ireland's constitutional position?
Micheal Martin's comments suggest that he doesn't regard the PM as an unambiguous unionist. Indeed, his "what if?" question re England getting "turned off" Northern Ireland is a question I have heard raised within unionist, loyalist and civic unionist circles.
It's the asking of that question which has convinced elements within nationalism that there are enough ambivalents, persuadables and agnostics from a pro-Union background to deliver a majority for unity in a border poll.
John Cole, a former political editor for the BBC, once told me: "When a politician says something unexpected you must immediately ask yourself why he said it and why he chose that moment to say it."
I don't know why Micheal Martin said what he said, although I'm pretty sure he knew the impact it would have on unionism.
I don't know why he chose to say it a few days after what Arlene Foster described as a "positive" North South Ministerial Council plenary.
But I do know that he has given the very clearest impression of interfering in local Northern Ireland politics and playing the "you're really a place apart" card.
Of course, whether it all amounts to a hill of beans is anybody's guess. "Beefing-up" can take many forms and mean many things, and he has so many other problems on his plate that I'm not convinced he would be stupid enough to open a new battle front with unionism inside and outside the Executive.
That said, within a few weeks of taking office he has chosen to have a pop at unionism - a very odd thing to do when the "two distinct political jurisdictions" really do need to be working together.