As Northern Ireland marks its centenary with resounding affirmations about the strength and lasting qualities of the union, that entity has in reality never looked more vulnerable.
Centrifugal forces of nationalism, amplified by Brexit and the grim prospects of seemingly never-ending Tory rule from Westminster, have turned tomorrow's regional elections in Scotland and Wales into key trials of strength over the future integrity of the UK.
The union may not be on the ballot paper in Scotland, but it has dominated a campaign which has revolved around whether a solid independence majority in Holyrood would represent an unanswerable moral, if not legal, case for another referendum on independence.
The unionist parties – a much-diminished Labour, once Scotland's dominant political force, as well as the Tories and the Lib Dems – have sought to portray the issue as a divisive distraction at a time when the UK must concentrate on recovery from the pandemic/Brexit/Tory rule.
Sturgeon, who has demonstrated great competence as First Minister, has played her hand with moderation and skill
And yet the history of Northern Ireland would suggest that time and again the refrain “let’s all just come together and make this election about our common problems” is one that falls on deaf ears in polarised communities where the nationalist (and in Ireland’s case, unionist) siren calls for easy scapegoats are all too addictive.
Opinion polls suggest that a clear independence majority is likely to emerge from the election in Scotland. The Scottish National Party (SNP), with the wind in its sails, may do it on its own, but, with Green support and a few likely seats from Alex Salmond's breakaway Alba party, it should be ready to confront Westminster with a complex democratic challenge. Is London really willing to say there is no democratic route for the Scottish people to express their desire for a say?
SNP leader Nicola Sturgeon, who has demonstrated great competence as First Minister, has played her hand with moderation and skill. If she is forced down the road of defying Westminster by unilaterally calling a referendum in Scotland, the argument that she had any alternative will be hard to make.
But Sturgeon has also lost some ground in the broader argument for independence with the SNP failing to answer difficult questions about how it would deal with a trade border with England required by EU membership, and a currency border.
Labour is likely to continue governing Wales, although it may have to share power with Plaid Cymru. Backing for independence stands at only 24 per cent in the polls, but there has been a surge among young voters for the idea. Labour hopes to counter that by pressing Boris Johnson for greater powers for the Welsh parliament.