AFTER THE 2017 UK general election, the DUP emerged as one of the most important groups in Westminster – offering the Conservative Party the promise of a majority in the House of Commons.

The confidence and supply agreement secured between Theresa May and the party basically offered Arlene Foster the final say on whether or not any negotiated Brexit deal was acceptable.

For two years, the DUP position was simple – the entirety of the UK had to leave the EU on the same terms. Put simply, Northern Ireland wasn’t to be left behind.

It was this dogmatism that both defined the parameters of the Brexit negotiations and helped scupper May’s own Withdrawal Agreement.

This makes the convolutions carried out by the party leadership in recent days, as they offered their approval to Boris Johnson’s Brexit plan, harder to understand.

Here’s a timeline of the DUP’s position on Brexit, the backstop and the border.

June 2017

Following the general election, which proved disastrous for May, speculation began about the role that the DUP would play in propping up the Tory government ahead of Brexit negotiations.

“The union is our guiding star,” Foster said, as she promised to help secure the best deal for Northern Ireland and the UK.

November 2017

Foster told delegates at her party conference that the DUP will prevent any Brexit deal that would “decouple” Northern Ireland from the rest of the UK.

She said that she had received assurances from May that there would be no “internal barriers” between the North and the UK after Brexit.

“No such internal barriers will be countenanced and… as we joined the then-European Community as one nation, will leave as one United Kingdom,” she said.

December 2017

Just as the divorce deal between the UK and the EU seemed finalised, with regulatory alignment between both sides of the border agreed in principle, Arlene Foster issues a statement rubbishing the plan.

“We have been very clear. Northern Ireland must leave the EU on the same terms as the rest of the United Kingdom,” she said.

And in a phone call hastily staged between the DUP leader and the prime minister, Foster was assured that there would be no border in the Irish Sea, effectively delaying what many had initially expected to be a major breakthrough.

Arlene Foster agreed a deal to support the Conservative government. Source: PA Wire/PA Images

February 2018

The UK government rejected the EU’s initial plan for a Northern Ireland-only backstop.

The proposal, which the EU suggested as a way to avoid a hard border in Northern Ireland, provoked an angry response from the DUP.

On 28 February, the DUP’s Nigel Dodds said that “we did not leave the European Union to oversee the breakup of the United Kingdom”.

It would, he said, be “catastrophic” for the North to be cut off from UK markets.

October 2018

Foster deployed a quote that would become representative of both the DUP’s intransigence and the party’s dogged negotiating position.

“There cannot be a border down the Irish sea,” she told the BBC in an interview. “The red line is blood red.”

This message – which harked back to the old idea that people signed the anti-Home Rule 1912 Ulster Covenant in blood – was the clearest rejection by the DUP of no regulatory divergence between the UK and Northern Ireland.

November 2018

When Theresa May published her doomed Withdrawal Agreement, it contained a UK-wide backstop in order to avoid a hard border.

But the agreement was condemned when it proved unacceptable to the DUP. The reason? It contained provisions that would lead to regulatory differences between the North and the rest of the UK, with Northern Ireland following some EU rules and with no say for Stormont on when the backstop could be exited.

The DUP’s response was to wobble the confidence and supply agreement by abstaining on some key votes in the House of Commons – basically firing a warning shot to Theresa May.

“You’ve got to keep your side of the bargain, otherwise we don’t feel obliged to keep ours,” the DUP’s Sammy Wilson said at the time.

Crucially, the issue of regulatory divergence was still a key issue for the DUP.

March 2019

Even as May was promising to resign if MPs backed her Brexit deal, the DUP were still not happy. The party called the plan an “unacceptable threat to the integrity of the United Kingdom” – once again referring to the threat of regulatory barriers between the North and the rest of the UK.

End of May’s premiership

Theresa May’s repeated failure to get her deal through the House of Commons can be traced back to her inability to placate the DUP.

After the Withdrawal Agreement was defeated for the third time, Nigel Dodds said:

There is the strong possibility that we could have a long-term outcome whereby Northern Ireland would inevitably pull away from its biggest trading market in Great Britain as there would be new internal barriers within the United Kingdom.

What happened next?

Last week, the DUP did something unthinkable. The party accepted a regulatory border in the Irish sea.

Boris Johnson meets Arlene Foster at Stormont in July. Source: Niall Carson/PA Wire/PA Images

Boris Johnson’s proposals mean that Northern Ireland would leave the EU’s customs union, but would create an all-island regulatory zone on the island of Ireland covering goods and agri-food.

Stormont would be able to vote on the regulatory arrangement every four years.

It was this concession, which would effectively amount to a DUP veto on any further regulatory difference after four years, that seemed to secure the party’s support.

Helpfully, the party was also offered extra funding to Northern Ireland.

Reacting to the deal, the DUP said it offered “renewable democratic consent” – apparently enough to convince the party to accept the plan.

These proposals, which are entirely consistent with the spirit and principles of the Belfast Agreement, demonstrate commitment to working with our neighbours in the Republic of Ireland in a spirit of mutual co-operation whilst respecting the integrity of Northern Ireland’s economic and constitutional position within the United Kingdom. They also protect the integrity of the institutions created by the Belfast and St Andrews Agreements.

What now?

After the meeting between Taoiseach Leo Varadkar and Johnson during the week, hopes have been raised that some kind of deal – perhaps with a referendum on the backstop alternative as opposed to an Assembly vote – could be agreed in the coming days.

What this means for the DUP is hard to say. The party, which started out in 2017 basically able to dictate whether a deal succeeded or not, has now lost considerable influence as Johnson has watched his majority slip away even with their support.

So while the party’s position is still important, it may no longer prove to be the sole gatekeeper that determines whether a deal can or cannot pass parliament.

Such a situation is clearly on the DUP’s mind. In a statement issued on Friday afternoon, amid speculation that Johnson might be edging towards a compromise, Foster warned: “The DUP is very relevant in the Parliamentary arithmetic and regardless of the ups and downs of the Brexit discussions that has not changed.”

If Johnson does offer a further compromise on his Brexit plan, then it’s difficult to predict how the DUP will respond.

Having already stepped over their own blood-red line, the party now may have little choice but to bind themselves to Johnson’s Brexit plan come what may.