It would do no harm for Sinn Feiners to reflect on the marvel that the Irish border is now at the very heart of political contention between Britain and Ireland - and that they can take no credit for having put it there.

Not a bullet, or a bomb, had anything to do with the fact that a test of competing vetoes between the Irish government and the DUP will decide the status of that border.

Britain is snared on that question as surely as if the border was a fault-line and Theresa May had caught a heel in the crack.

But nothing the Provisional movement did over 30 years of trying to force the British and Irish governments to rethink partition has contributed anything to this circumstance.

And there appears to be nothing much that Sinn Fein can do right now to influence the outworking of this contest.

Yes, uppity Tories who can't get their heads round the fact that Ireland is an independent state with interests to preserve are kidding themselves that this whole deadlock is a game to outflank Sinn Fein. They don't see that this attitude further appals the Irish.

Yes, we knew that some sectarian unionists couldn't credit nationalists with political maturity, but we hadn't grasped that so many Tories didn't even think Ireland was a country.

At least the weapons being wielded now are purely political and parliamentary.

The champion of the Irish demand that the border remain as invisible as heretofore is not Gerry Adams, Cu Chulainn, or the ghost of De Valera. It is Leo Varadkar, a politician whose name many journalists have yet to learn how to spell.

He is the leader of Fine Gael, the party which riled republicans down the decades by refusing to identify with any pan-nationalist project.

He perplexes many British politicians and political commentators, who can only imagine that he is motivated by a sinister impulse to drive forward a republican agenda, though in this case that is as likely as Jeremy Corbyn kissing Donald Trump on both cheeks.

Varadkar insists that he is not trying to unite Ireland, or at least that that is not the motivation for his threat to veto Britain's move to phase two of the Brexit talks.

Still, his steady nerve - so far - is garnering support, uniting more of his country behind him.

And there is also a realistic prospect of Brexit bringing a united Ireland closer.

Northern Ireland is the one part of Britain in which people, if they are unhappy with the outcome of the Brexit talks, or the actual outworking of Brexit itself, can vote themselves back into the EU through a border poll.

Given that the majority here voted Remain, all it takes is for that majority to hold for a few years, enthused perhaps by British economic decline, or the continuing depletion of the health service, and it would be a very blithe unionist who would sleep easy at night.

But how well would you sleep if you had promoted murder and sabotage for decades to force this prospect, only to discover that your efforts were entirely fruitless and that English nationalism, instead, would raise the prospect of your dreams coming true?

You might hope that those chauvinistic Brits, dreaming of taking back control of their borders, would further exacerbate the problem. Indeed, if they come to the conclusion in the coming days or weeks that their Union with Northern Ireland only spoils their Brexit for them, they might start thinking of ways to be rid of us.

But, again, these are fancies that the Provo mind can relish but neither take credit for, nor actually realise. They were to be the vanguard of freedom, but they are now at the sidelines of history.

The champion of the Union now is the DUP, doing the job it was created to do, defending the Union with Britain as inviolable.

Destiny has also delivered a marvel to them. It has equipped them with a veto over Britain's advance to phase two of talks. And their veto is every bit as effective as Ireland's.

They have tested it in the full heat of battle and found that a single phonecall could bring Theresa May scurrying back from Brussels to rewrite a deal which her own judgment had said was fine.

They have lost the run of themselves and fail to see that they might be damaging the Union they love.

Sinn Fein has one weapon it can use against the DUP - it can block their return to Stormont.

They have another, but they refuse to use it. They could take seven seats in Westminster, which might turn out to be very decisive in the new volatility created by the clashing vetoes of Ireland and the DUP.

We might easily see a split in the Tory party, as hard Brexiteers sicken of May's malleability. We might see votes which are very narrow indeed. We might see a General Election in the spring and a further effort to find a Prime Minister who can deal with Europe.

Sinn Fein's abstentionism belongs to a period of republican purism that ended in the 1980s. The party decided then to enter parliamentary politics, but only in Dublin and in local government, and then in Stormont, but not in Westminster.

Sinn Fein is a parliamentary party with parliamentary skills and experience.

It exempts itself from parliamentary combat, because it wants to go on believing that it is a purely principled revolutionary movement that has conceded nothing to political parliamentary expediency.

It is self-deluded. It clings to its principle in only one forum, like a vegetarian who thinks it is okay to eat fish and chicken and that, so long as he doesn't eat red meat, he can still call himself a vegetarian.

But here's a scenario. What if withholding those seven votes, either in this parliamentary term or another, was to land us with a hard Brexit, a British walkout of the talks and a hard border?

Sinn Fein would then have reinforced partition when faced with a prospect of bringing the two parts of Ireland closer together.

Then again, maybe Sinn Fein likes the idea of Brexit. Maybe it secretly hopes that the disruption it will cause will be the more likely route to Irish unity. After all, they did very little to prevent the Leave vote, hardly campaigned at all.

Well, that would be their form. But even then they would have English nationalists to thank for the crisis and for the opportunity that England's difficulty has traditionally been.

And their 'war' would have had nothing to do with it; history would record it as a digression.

Belfast Telegraph