That the Northern Ireland state was constructed around a unionist majority has long been a sore subject, sharpened as that majority recedes and this year's centennial comes into focus. Brexit's outworking in the shape of checks at Northern ports has heightened tension, as it was bound to do.
Is widespread, serious loyalist violence likely? Will the unionist parties pull out of Stormont? That such scenarios are broached is the unfortunate outcome of post-Brexit unionist disarray. The strongest counter-proposition is that paramilitary loyalism is in a similar state.
The DUP's portrayal of Brexit as wholly good for Northern Ireland was always going to clash with reality. Embattled leader Arlene Foster has tried to model calm on a surface ruffled by fiery bombast from MPs Sammy Wilson and Ian Paisley. Recent polls that predicted the break-up of the UK and put Sinn Féin on course to take the first minister post next year also predicted DUP seat losses to the articulate Jim Allister, until now a one-man party of unassailable negativity. A year is a long time, especially in this Covid age. The DUP nonetheless appears rattled.
Lifting the customs checks required by the protocol agreed between the EU and the UK came in a rush this week in the name of protecting workers at Larne port. The substance of rumoured threats to them remains unclear.
With a soundtrack of loud unionist complaint of aggression and hostility from the EU and the Republic, the febrile micro-climate looked like a tactic left over from the late Rev Ian Paisley's toolbox, before the DUP founder somersaulted to lead Stormont with former IRA leader Martin McGuinness.
Comparison may be inevitable but is misleading. The Stormont department headed by the DUP's Edwin Poots, whose anti-protocol rhetoric was at odds with his responsibility for signing off on the port check structures, directed the Larne move.
Level-headed security assessment, however, finds no evidence of loyalist paramilitary involvement. It has been reported that the council or others told police of the Larne port threatening behaviours, not the other way around.
There is a wider context too. The flags protest of 2013 left many in court, some openly resentful that political unionism had called them on to the street. Loyalist paramilitaries long ago dubbed Paisley Senior the Grand Old Duke of York. The gang bosses of the UDA and UVF, both still substantially armed, now spend most of their time fighting each other for control of drug deals, some reportedly involving dissident republicans.
Tuesday's walk back and forth through a Protestant east Belfast enclave by about 50 men with faces covered is believed to relate to an internal UVF tussle.