There was some good news for unionists in what happened politically in Belfast yesterday, and some not so good.
The good news is that the visit of the prime minister and the contents of her speech confirmed a pro Union direction of travel that has been slowly gathering pace as Brexit nears.
This is in part a result of the government being propped up by the DUP, and so being much more wary about what it concedes to Dublin than it might otherwise be, but it is also perhaps a reflection of a genuine unionism in the current generation of Conservative leaders.
As one Westminster grandee described it to me this week when I was in London, the previous generation of Tory leaders (Chris Patten’s era) saw Northern Ireland through the prism of civil rights and unionist wrongdoing.
That sort of outlook brought us the disastrous Anglo Irish Agreement of 1985 (the major problems with which unionists grapple today, including the partisan and interventionist approach of Simon Coveney, have their origins entirely in that pact).
The current generation of Conservative leaders grew up with the IRA terror campaign and are more instinctively unionist than the generations before it, my source said.
People from William Hague to Dominic Grieve to Ruth Davidson have made clear that an Irish Sea border of any description is unacceptable. The only senior Tory to say otherwise is Ken Clarke, who comes from that earlier generation.
But the instinctive rejection of a border in the Irish Sea, among politicians born in the 1950s and 60s, extends across the aisle, to the Labour Party.
When the prospect of such an internal frontier emerged last year, Keir Starmer was among the first and most emphatic critics of it (for pragmatic reasons of hoping to see the government fall, Labour has latterly been muted in its opposition to such a frontier, instead emphasising the importance of no hard land border).
But I also think that this genuine and instinctive unionism that prevails across the UK political establishment (ie that Northern Ireland is fully a part of the nation) has emerged more noticably in recent weeks because at times of political chaos (ie the last year) it takes a period of reflection for people to understand fully what is happening and to see the risks.
The very persistence and intransigence of the EU on its interpretation of the backstop has given influential people in London time to think of what an internal border might actually mean.
And unionists are lucky that the establishment has not, on reflection, liked that prospect.
Even I, who lives in Northern Ireland, briefly wondered if there was a way in which the Province could have the best of both worlds, EU and UK, post Brexit in the form of some special status, before quickly concluding we couldn’t.
Regulatory or customs divergence from Great Britain would be too great a breach and it would be irreversible. It would be the effective end of NI in the UK if, at a future date, Britain and the EU diverged more sharply (such as if Brexit began to be a success and the UK decided it could afford an even more independent relationship).
So it was in this relatively recent tradition of establishment unionism that Theresa May yesterday tried to assuage unionist anxieties, and did so in Northern Ireland.
Even so, there was an alarming passage in the speech, which Lord Empey has highlighted.
The prime minister greatly over emphasised the impossibility of even a slightly harder border as a result of the Belfast Agreement in her attempt to reassure nationalists and the Irish government.
In doing so she has given weight to what the London-based Northern Irish constitutional barrister Austen Morgan has previously described on these pages as “the myth of the Belfast Agreement,” which republicans are now trying to use in the courts, and might yet use to try and stop direct rule.
Mrs May, in trying to alleviate nationalists in this way while trying to avoid the EU interpretation of the border backstop, has in the process (and paradoxically) given weight to the EU’s decision to hone in on the border and say that a full Brexit on the island is contrary to the 1998 Belfast Agreement.
But there will be time in the coming days to consider the implications of those deeply troubling sections of the PM’s speech.
It would be churlish not to recognise, in the meantime, that Mrs May was not only keen to alleviate nationalist concerns about British intentions in Belfast yesterday, she was also trying to alleviate unionist ones — and to address the specific complaint, made in this newspaper and elsewhere, that London has been weak in defending the Union amid Dublin’s hardball tactics.
The concern that I mentioned at the top of this article, the possible ‘bad news’ for unionism from yesterday, is that her speech left unresolved many of the contradictions and complications of the Brexit goals and talks, and the political limitations caused by last year’s hung parliament. This, by common agreement, makes a ‘No Deal’ outcome more likely.
Aside from the administrative difficulties that will emerge with regard to a range of cross-border EU-UK interactions in a no deal scenario, it is likely to cause such anger across nationalist Ireland that it will lead to even more brinkmanship from Dublin and could even lead to some civil disobedience in border areas.
It is also possible that if the Irish question is seen to have thwarted a clean Brexit there will be a rise in the sort of English nationalism that would prefer to cut NI adrift rather than sacrifice a full Brexit.
In those dire circumstances, popular feeling could take over and the instinctive unionism of the London establishment could be cast aside.
Amid such fury on both sides of the Irish Sea, a government as constrained as this one could yet make sudden concessions that damage NI’s place in the Union.
All the way through this process a British Conservative government propped up by a unionist party has been as keen, if not more keen, to reassure a neighbouring jurisdiction that nothing will be altered at the point where the jurisdiction changes than it has been to defend it own unfettered sovereignty.
That was also the case yesterday in Mrs May’s speech.
What might the government’s approach be if tensions escalate massively in the event of no deal?
• Ben Lowry (@BenLowry2) is News Letter deputy editor