It is increasingly likely the scandal over a £400m botched heating grant introduced while she was enterprise minister, will force out Northern Ireland’s First Minister, Arlene Foster and possibly result in the collapse of the Northern Ireland Assembly and fresh elections.

If it does, it will be the first crisis in the history of the power-sharing executive that has been triggered by nothing more than garden variety ministerial incompetence. Northern Ireland will get past it and, compared to the crises that used to hit, Foster’s career is small beer.

But there is another significant threat to Northern Ireland’s political stability waiting in the wings.

At the root of it, is an age-old political truism. As each political generation changes, there is a temptation to revisit the certainties of the past by those who see themselves remaining true to the faith their predecessors drifted away from.

That’s certainly an explanation to describe what’s going on in the modern Labour party under Jeremy Corbyn.

It is also playing out in the Irish republican movement.

Last September, Gerry Adams revealed that he is thinking of stepping down as President of Sinn Fein after nearly 34 years in the role. Although tight-lipped on exactly when and in what circumstances, this is massively significant.

There are those within Sinn Fein who will no doubt spy an opportunity to park his baggage with him and automatically win a new hearing as a fully constitutional political party. However Adams has been seminal in splicing the political and armed wings of republicanism and his eventual departure may leave a bigger gap than intended.

His successor will come from a generation of Sinn Fein politicians that have not needed to make the epic political transition Adams has. Current favourite is his deputy, Mary Lou McDonald. She would certainly help cauterize some of the more troubling associations with the past. But would she have clout among the doubters, who look back at the certainty of the "armed struggle"?

Speculation also swirls around Martin McGuinness, said to be undergoing treatment for a, as yet, undefined illness. If anything, McGuinness is even more important than Adams. Not only is he Deputy First Minister, but as a former IRA commander who memorably left Derry looking "as though it had been bombed from the air", he is a talisman for rank-and-file Irish republicans. It was McGuinness who oonvinced many that the peace process was the best way forward.

Both McGuinness and Adams seem to have been around for ever. Both were part of a delegation from the IRA which participated in talks with the British Government as far back as 1972, while Adams has been President of Sinn Fein since 1983. Would successors to the Adams/McGuinness axis have the same clout in republican communities and also be able to maintain Sinn Fein’s political dominance? This point is far from academic.

There is a danger of the republican movement fraying at the edges.

A new, more militant republican party, Saoradh (Irish for "release") has recently been formed. This group curses Sinn Fein as "false prophets" for selling out. Meanwhile, People Before Profit, a collection of Marxists and community campaigners, won two seats in last May’s assembly elections - one in Derry, once very much McGuinness’ stomping ground, and one in West Belfast, Gerry Adams’ political backyard. A sign, perhaps, that Sinn Fein is no longer omnipotent in these areas.

Overall, the peace process has been transformational for life in Northern Ireland. But if you were poor and marginalised before it began, it’s pretty likely you still are. Irish republican strongholds like Derry and West Belfast still have among the highest unemployment rates in the UK.

For Sinn Fein, the price of political office is that at some level, the blame rubs off on you. Moreover, political radicalism is traditionally a means of accruing status in poorer communities. Being an "IRA man" was a badge of honour during the Troubles. The rhetoric of Saoradh and People Before Profit emulates the kind of Marxist, anti-imperialism sloganising that Sinn Fein abandoned a generation ago. As we are seeing across Europe, though, it is coming back into vogue.

Metaphorically – and literally - Sinn Fein’s opponents want to land blows. Two weeks ago, Gerry Kelly, a prominent Sinn Fein figure, was attacked on the street in Belfast. The circumstances are not clear yet and a 21-year-old man was arrested.But Kelly, architect of the Maze prison escape in 1983 – the biggest since Colditz – was once regarded as untouchable.

And while dissident republican paramilitaries are heavily infiltrated by the still sizable British intelligence presence in Northern Ireland, they only need, as the old saying goes, to be lucky once.

The fear must be that any changing of the guard at the top of Sinn Fein will open the way for a fissure in the republican movement, which may in turn destabilise the broader political system. With her casual pledge to abolish the Human Rights Act, (a key assumption underpinning the Good Friday Agreement) and the mess over border arrangements with the Irish Republic post-Brexit, it is clear Theresa May does not have her eye on the ball .

Despite these last two decades’ worth of incremental progress, Northern Ireland’s peace process requires constant vigilance. Even after the emergence of "normal" politics (normal for Northern Ireland), the system is not too big to fail.

Kevin Meagher is a former Special Adviser to Labour Northern Ireland Secretary, Shaun Woodward. He is also author of A United Ireland: Why Unification is Inevitable and How It Will Come About published by Biteback.