The Democratic Unionists are standing firm in their opposition to Theresa May’s deal.
The Northern Ireland party, whose 10 MPs prop up Mrs May’s minority government, has made clear it will not be backing the agreement without changes to the contentious border backstop.
So why is the backstop proving such an obstacle?
– What is the backstop?
In simple terms, it is an insurance policy written into the withdrawal treaty that will ensure, come what may in future trade talks, that the Irish border will remain free flowing post-Brexit.
Activated if a wider trade deal fails to materialise before the end of the Brexit implementation period (currently December 2020, but it could be extended), the backstop would see the UK, as a whole, enter into a temporary customs union with the EU – to avoid the need for customs checks on the 310-mile frontier.
Crucially, it would also see Northern Ireland adhere to EU single market rules on goods – again to rule out the necessity for border regulatory checks.
– Why is it needed?
For the EU, and the Irish Republic in particular, the backstop was a fundamental requirement of any exit deal struck with the UK.
While the shape of the future relationship was to be hammered out in phase two of the negotiations, Brussels and Dublin demanded the mechanism in phase one, to guarantee the border would always remain open, regardless of what the future held.
Their case was two-fold – economic and political.
They argued that any customs or regulatory border would have a devastating impact on the economy of the island.
Brussels was also determined to protect the integrity of its single market, amid fears an open land border with the UK could see goods which do not meet Brussels’ regulations pass into the 27 member states.
But the Irish border is much more than a trade crossing. It is a highly sensitive political construct; a physical manifestation of the constitutional dispute between nationalism and unionism.
Heavily fortified during the Troubles, the border has become almost invisible since the peace process – with people and goods moving freely between north and south.
Despite differences on many things, there is almost universal political consensus across the island that any return to checkpoints on the border would be a backward step.
– So if the DUP does not want to see a hard border, why is it opposed to the backstop?
While keen to avoid any border checks, the DUP has made clear this must not come at the price of erecting new barriers in the Irish Sea.
The party fears that is what the backstop will deliver.
Binding Northern Ireland to single market rules would create a regulatory border between the region and the rest of the UK, the DUP contends.
It believes this would not only be bad economically – insisting GB is NI’s biggest market – but would also undermine the constitutional integrity of the UK.
Many Brexiteers also fear the backstop could lock the UK into a permanent customs union with the EU – thus preventing it from striking lucrative new trade deals and fulfilling the promises of the 2016 referendum.
But, for the DUP, the Union comes above everything. Yes, it supports Brexit, but that is not its raison d’etre. The Union of Great Britain and Northern Ireland is.
The party could potentially stomach the backstop if it was time-limited, or if the UK could pull the plug when it wanted. The withdrawal agreement contains neither provision, with the measure theoretically remaining in place “unless and until” alternative arrangements are found.
– What has Theresa May done to try to convince the party?
After her deal’s first thumping defeat in the Commons, Mrs May went back to the EU to try to gain concessions on the backstop.
She secured a number of legal add-ons to the agreement – documents the Government insisted provided assurances around the temporary nature of the measure and over potential routes to exit it.
Mrs May has also sought to provide reassurances to the DUP in the form of domestic law, pledging a beefed-up role for Stormont on backstop matters and commitments that the rest of the UK will not diverge from the EU regulations Northern Ireland would have to abide by.
– Why haven’t those shifted the DUP?
The party insists Mrs May’s assurances fall short of what they require.
While it has stepped back from its initial demand for the backstop to be binned completely, it has remained steadfast in its call for treaty level changes to its design, to guarantee it could only ever be temporary.
For the DUP, the Prime Minister has failed to deliver such a guarantee.
In that respect, the advice of Attorney General Geoffrey Cox was significant.
He said while the new assurances from the EU had “reduced the risk” of the UK being held in the backstop indefinitely, the risk still remained.
The DUP has also not been swayed by pledges on new domestic laws to keep Northern Ireland aligned with GB.
Such laws could be scrapped by a different government in the future and, moreover, domestic legislation will always be trumped by the terms of the withdrawal agreement, as it holds a greater legal status as an international treaty.
– So does the DUP represent the majority view in Northern Ireland?
On the wider Brexit debate, Northern Ireland voted 56% Remain in the 2016 referendum.
A majority of the members elected to the currently defunct Assembly in 2017 are from pro-Remain parties.
In regard to the withdrawal agreement, those same parties back Mrs May’s deal, arguing that it is better than no deal at all.
And in relation to the backstop, those parties are actively in favour of the measure, insisting it is a vital mechanism to avoid a return to the borders of the past.
All the main business and agriculture groups in Northern Ireland are also in support of the deal – a stance that has on occasion brought them into open conflict with the DUP.
The decision of the influential Ulster Farmers’ Union (UFU) to publicly back the deal has proved particularly awkward for the DUP, given its support base is traditionally drawn from rural hinterlands.
Yes, the DUP do hold a majority of Northern Ireland’s Westminster seats (10 of 18).
Notwithstanding that, the region’s complex political history means the pro-agreement viewpoint has not been articulated as loudly as it might otherwise have been in the Commons.
Sinn Fein’s long-standing abstentionist policy means its seven MPs do not take their seats, leaving independent North Down MP Lady Sylvia Hermon as the sole voice in favour of Mrs May’s withdrawal agreement.