To paraphrase Shakespeare, "When political sorrows come, they come not single spies, but in battalions." A few weeks away from the UK's formal departure from the EU (and there's still no certainty about whether there'll be a deal) and five months from May 3 (May 3, 1921 was when Northern Ireland came into existence), unionism is confronted with a battalion of sorrows and challenges, all of which it must address and resolve if unionism - and Northern Ireland itself - is to survive. Here are some of the main ones.
Demographics. This is often assumed to mean the next census will, for the first time, indicate there are more Catholics than Protestants. I don't actually subscribe to the view that a Catholic majority, in and of itself, spells the end of the Union; although we can't ignore the fact that most electoral evidence suggests Catholics rarely vote for unionist parties.
But demographics is about much more than a crude headcount, it's also an important guide to the multiplicity of structures within a population.
For instance, demographics gives us information about the concerns and intentions of those who were voting before the Good Friday Agreement and those - now reaching their early 40s, or just turning 20 - who only began voting after 1998. It indicates key differences between those who lived through the Troubles and those who have no personal memory of it.
It highlights the differences between liberals and conservatives on specific socio-economic/constitutional/ethical issues. It gives us information on how unionists respond to environmental issues.
Indeed, it also allows us a closer look at the differences (many of them very nuanced) between party-political traditional unionists and those who might be described as "small-u", or "civic", unionists.
If it is to survive and expand its voting base, then unionism needs to drill down into all of the demographic groupings (and that, of course, means providing the necessary financial and research resources to identify the groups) and develop policies which can attract new votes, particularly within the post-1998 voting groups, into the pro-Union camp.
A closer look at the demographics more inclined towards nationalism and Irish unity is vital, too.
It also needs a forensic look at that crucial pro-EU vote within unionism which voted Remain and is unhappy with what is sometimes described as the DUP's uber-unionist approach since 2017. While it is true that it doesn't automatically follow that a Remain-voting unionist would vote for Irish unity in a border poll, it is reasonable to assume that a smallish, albeit crucially important, number of them might prioritise the EU over the UK.
And that smallish number could grow if Boris Johnson's deal nudges Northern Ireland - as it seems to be doing - into something resembling a granny-flat status perched somewhere between the EU and the UK.
The other thing unionism needs to be aware of is the ongoing narrowing of the voting gap between it and other constitutional options. In 2017, unionism, for the first time ever, lost its position as the majority within a local parliament, or assembly.
In December 2019, unionists represented a minority of MPs returned from Northern Ireland.
And, if you drill into the political allegiances of the 462 local councillors, you'll discover that unionists (those who described themselves as such in their election literature) are also in the minority.
Again, none of this means that unionism is on an unstoppable decline, but it does mean it must acknowledge there is a direction of travel and then develop strategies and policies to address the problem.
It must also face the reality that a border poll, while not inevitable, is certainly more likely than not. Both Leo Varadkar and Micheal Martin take the line that now is not the time for a poll, yet in the question-and-answer session after his recent speech about the coalition's Shared Island approach, Martin mentioned a couple of times about not wanting to consider it for at least five years.
Five years is the blink of an eye in political terms. Civic nationalism in Northern Ireland, along with Sinn Fein and the SDLP, is focusing a lot of attention on unity right now.
And, while the Irish Government doesn't have the issue at the top of its agenda, I think it would be remarkably complacent of unionism to assume that work isn't being done in the background. My assumption, for what it's worth, is that the Irish Government is now proceeding on the basis that a combination of circumstances will make the demand for a poll irresistible.
A much bigger problem for local unionism can be summed up in a pressing existential question: will the UK in its present form (dating to just 1921) survive? Last week, Boris Johnson announced he would be creating a task force to make the "emotional" case for the Union, although he was typically vague about what he meant by "emotional".
It didn't help that he also chose to attack devolution and managed to make it sound like people in Scotland, Wales and Northern Ireland weren't really fit to manage their own affairs. As ever with Johnson, he completely avoided his own, catastrophically inept, role in the mess that has led millions of people to wonder if the EU is preferable to the UK.
If the SNP wins well in the Scottish elections next May and wins on the back of a demand for a second referendum on independence, I think the only "emotional" response Johnson can expect is one of extreme anger if he chooses to ignore that demand.
And if the reality of his EU withdrawal deal (which I still expect him to agree) is that Northern Ireland is even more of "a place apart" than before, then I don't know what sort of "emotional" response he'll get from unionism. But I can guess.
The other problem for Johnson (and, by extension, for Northern Ireland unionism) is that he is still playing cards which were dealt to him by a re-energised English nationalism in December 2019. That's the voting base which gave him his majority and it's a base which doesn't give a damn about the Celtic fringes of the UK.
Indeed, all the evidence suggests that base would be happy to let Scotland and Northern Ireland go in exchange for a clean break from the EU. And with Nigel Farage rebranding the Brexit Party as Reform UK in time for next May's local government elections in England, Johnson will be cautious about anything which could be interpreted as compromise.
In the run-up to next May, unionism and the assorted loyal orders will be preparing to celebrate Northern Ireland's centenary. What is the value of the Union? What is the role of "Ulster" unionism within the broader UK/British identity? How is our local unionism celebrated against a potential background in which a British Government has agreed a deal which loosens Northern Ireland's constitutional links with the rest of the UK?
What does it mean to be a unionist in a UK where there are a number of competing nationalisms and identities? Who, from across the UK, will come to Northern Ireland to champion the Union: Johnson? Rees-Mogg? Nigel Farage? Members of the ERG?
Whatever unionism will be celebrating in the next few months has to be something which is capable of building and sustaining majority approval in the event of a border poll.
All of which means that unionists need to be talking to each other right now and putting in place the structures and policies required to grow and maximise the pro-Union vote. A few speeches from Arlene Foster and Steve Aiken, along with some Orange Order events, won't be enough.
Unionism is a huge, diverse and fractious community. I think it was Bill Craig who described it as a church so broad that it accommodated competing choirs, congregations, ministers and versions of the Bible and with an insatiable appetite for further division and new voices. That would have been around the mid-1970s. And to be honest not a lot has changed since then.
Where we are right now represents an existential crisis for the UK and for Northern Ireland unionism. It doesn't mean there will be an overnight collapse, but it does mean that everything is in play.
There is no room for Johnson's rebooting of "plucky old Blighty" jingoism, or for an "it'll be all right on the night" dismissal of fears by elements of unionism here.
To be honest, I can't think of a worse, more ill-fitted, champion of the Union than Johnson, who seems to do more damage to the concept of a renewed UK with every speech and throwaway line.
I also fear the DUP is more concerned with itself and its own electoral prospects than in building a case which is inclusive, rather than exclusive.
The next five years will probably decide the existential question one way or the other. Unionism, across the entire UK, cannot waste that time.