As nominations close for the general election, Northern Ireland promises a cockpit of unpredictable contests. Brexit has turned out to be the biggest challenge facing unionism since the Good Friday Agreement negotiations. The outcome on December 12 could well determine the future of Arlene Foster's leadership of the DUP.
At issue is her party's unequivocal support for Brexit since the 2016 referendum.
For all its successful efforts to stymie a backstop deal between London and Brussels, the DUP is accused of breaching its red line on a "border down the Irish Sea" by belatedly agreeing to some form of regulatory checks and taking the new Prime Minister Boris Johnson on trust that turned out to be misguided.
As a result the gloves are off between the DUP and the Ulster Unionists as to whether Northern Ireland's position is more secure inside or outside the EU and whether to leave or to remain is the better option.
Every past unionist leader since Carson and Craigavon has had the same simple and easily understood rallying cry: vote unionist to protect and save the Union. But Brexit casts a dark shadow, as the past three years have shown.
As of now no unionist - or nationalist for that matter - can be sure what even the immediate future holds for this island. This general election promises to be like no other before.
The outcome in at least six constituencies is far from a given. The bookmakers' early odds on who might win or lose reflects a mood of deep uncertainty and confusion in the unionist community.
Of course, in some constituencies there are still racing certainties. At least five cast-iron seats for the DUP, four for Sinn Fein. The two big parties are also hot favourites to take their tally to six each in three other constituencies.
It's the rest that leave a big question mark hanging over December 12. For example, the battle for Belfast's representation in the next Parliament at Westminster is particularly hard to call.
If the bookies are right - and they are seldom wrong - the DUP will still win South Antrim, East Belfast and North Down, and lose South Belfast to the SDLP.
The tightest of all contests is North Belfast, but if the DUP's deputy leader Nigel Dodds were to win, then the party could return to Westminster with the same number of seats as last time. However, this is a big "if" for the DUP.
It would take very little deterioration in the party's electoral support and rise in the fortunes of the Ulster Unionists in South Antrim, or the Alliance Party in East Belfast and North Down, or Sinn Fein in North Belfast, to leave the DUP with as few as six or seven MPs.
The most significant DUP figurehead, Dodds will need every unionist vote he can get to survive as an MP. The party's chances of maintaining the crucial balance of power at Westminster will be greatly diminished if it returns fewer MPs.
If that were to happen, it would be a body-blow of immense proportions for Foster and Dodds' leadership and call into question whether she could continue - irrespective of the findings of the RHI Inquiry report, which is due for publication early next year.
The stakes could not be higher for the DUP. The party's pivotal role in Brexit is under an electoral microscope.
The main unionist party finds itself, for the first time in the history of Northern Ireland, in a minority position on such a major constitutional issue as the UK leaving the European Union.
Also alarming for unionists must be the opinion polls, which show many people in Britain - Leavers and Remainers alike - profess to have little or no concern for Northern Ireland's position in the Brexit debate. Unionists appear as riven with division and argument over Brexit as the rest of the UK, as evidenced by the scathing attack on the DUP from the Ulster Unionist Party's Steve Aiken in his very first speech as leader.
Clearly, there will be no meeting of minds, other than for the expedient reason to deny Sinn Fein a seat in marginal constituencies.
The major unionist party, having nailed its colours so unequivocally in the 2016 referendum to Brexit, now finds itself assailed from all sides in Northern Ireland; by the 56% who voted Remain; by the new Ulster Unionist leader, who says the DUP has "sold out on the Union"; by virtually everyone in the nationalist and republican community; and by the centre ground of Alliance.
If the original founders of unionism could return today, they would surely be shocked to find such dissent and disarray, made all the more evident in 2019.
The old unionist order has changed utterly.
From majority rule for half-a-century to no rule for three decades, to sharing power with nationalists in the past 20 years, and now to the ungovernable Stormont of today.
The Brexit referendum and its aftermath has opened a can of unwelcome worms. Some say, had they known in 2016 what has dawned on them now, they might not have voted as they did in the referendum. How many take that view remains to be seen in a month's time when their votes are counted.
As of now, the future direction for unionism and for Northern Ireland looks decidedly uncertain. No one can convince the electorate here of what a border down the Irish Sea may or may not mean.
No one can be sure what - if any - influence unionists will have in the next Parliament, or whether people across the water care any more as to Northern Ireland's future relationship with Europe or Britain.
Nor do the people of Northern Ireland have any guarantee of how they will be governed in future, either from Stormont or from Westminster - or from Brussels.
Perhaps the unionists in general who voted as they did to leave in the referendum did not think it would come to this - but it has.
Another major milestone beckons, for better or worse, following on so many over the past 50 years - from the fall of Stormont in 1972, to the Anglo-Irish Agreement in 1985, to the Good Friday Agreement of 1998.
What next? The election on December 12 will decide not only the future of the United Kingdom, but also the way forward - or back - for Northern Ireland and unionism in the coming decade.
It is as serious as that.