After a turbulent election last week – one in which Theresa May lost her parliamentary majority and with it the strong mandate she said she needed to be able to forcefully negotiate the UK’s exit from the EU – the British Prime Minister is currently fighting for her political life. With some desperation, she is attempting to form a coalition with Northern Ireland’s hardline Democratic Unionist Party.

In doing so, she looks set to take the UK’s current political crisis to another level.

After a successful election, the DUP is now the fifth largest political party in the UK Parliament. Yet it remains one of the most extreme political entities in mainstream British politics.

During the party’s four-decade history, queries over the DUP’s links to protestant paramilitary groups have never really fully gone away. These groups, known since the outset of the sectarian “Troubles” that plagued Northern Ireland for much of the latter part of the 20th Century, as “loyalists” – as in “loyal” to the British Crown – were, to speak plainly, murderers and terrorists. The consequences of Theresa May’s dalliance with the party could therefore be considerable – for the UK’s relationship with the Republic of Ireland, for the Northern Irish peace process and even for the long term reputation of the British Conservative Party, which May currently leads.

The DUP was formed in 1971 by the Reverend Ian Paisley, a fundamentalist Protestant preacher who had previous close associations with loyalist paramilitary groups. These groups formed to counter an increasingly popular liberal civil rights movement that sought to end widespread discrimination and police brutality against Catholics.

The formation of these Protestant paramilitary units, together with a reboot of the Catholic Irish Republican Army (IRA), started a bloody sectarian struggle that lasted from the late 1960s until a fragile peace process was brokered – by London, Dublin, Belfast and Washington – in the 1990s.

The backdrop to all of this is the “800 years of rule,” as it is commonly described, by first England, then Great Britain, over the Irish. After a brief civil war in 1919, the predominantly Catholic Republic of Ireland formed to break away from the United Kingdom. But the northern corner, with its significant populations of “loyalist” Protestants, remained a part of the UK. This became Northern Ireland.

In the election campaign, Theresa May’s rival, the left-winger Jeremy Corbyn, was castigated by the populist pro-May mainstream press for his one-time links with Sinn Féin. How, many are asking, is this any different?

The modern DUP has tried hard to move with the times in post-Troubles Northern Ireland. It now sits firmly on the centre stage, along with the Catholic, pro-Republican Sinn Féin, which is historically linked to the IRA.

Yet the DUP remains proudly hardline conservative, opposes same-sex marriage and abortion and is firmly Eurosceptic. The DUP campaigned for Brexit, although this position is complicated because of the land border that Northern Ireland shares with the Republic of Ireland, which will remain an EU member. The DUP, along with almost everyone else in Northern Ireland, realizes a “hard border” EU frontier with control and checkpoints would benefit nobody.

Theresa May is seeking a coalition, on an ad hoc “confidence and supply” basis, with the DUP, to give her minority Conservative government the necessary boost that will allow it to keep power. In return, the DUP have, during negotiations over the weekend, asked for an economic aid package for Northern Ireland and an assurance that there will be no referendum on Irish unity.

The Irish Prime Minister, Enda Kenny, called Theresa May on Sunday to express his concern over any possible deal with the DUP and Sinn Féin have described the relationship as a “betrayal.” Many are asking how the British Government can remain impartial in governing a peace process while at the same time forming an alliance with one side. In the election campaign, Theresa May’s rival, the left-winger Jeremy Corbyn, was castigated by the populist pro-May mainstream press for his one-time links with Sinn Féin. How, many are asking, is this any different?

There can be very few who would want to see the guns and bombs return to the streets of Northern Ireland but the peace that is in place is still, after more than 30 years, brittle and conceals a deep entrenched bitterness. The rumors coming from May’s own party say it is now not a matter of if she will leave office but when. For the moment, her own political crisis has pushed an older conflict to the surface.

May’s troubles have their roots in 2013, when then Prime Minister David Cameron announced the British people would be allowed to “have their say” on European Union membership. He did this because his Conservative Party was losing support to the far-right, anti-EU United Kingdom Independence Party (UKIP). He gambled, lost the vote – and his job – and the consequences, for the UK and for Europe, are still unravelling.

This election effectively saw the obliteration of UKIP. But a party even more extreme has now stepped into the spotlight, however momentarily. What that means for the UK, for Ireland and for Europe remains unclear.