LONDON — Thought Prime Minister Boris Johnson had, to quote his election slogan, finally gotten “Brexit done”?
After months of tension over the status of Northern Ireland, the British government has announced plans that would allow it to discard parts of a deal that Mr. Johnson proclaimed was “oven ready” after he negotiated it in 2019.
Some in Brussels speak of a threat to the integrity of the European Union; some in London and Belfast, of a threat to the coherence of the United Kingdom. And behind all the bluster lie fears about the fragility of peace in a region where decades of sectarian violence left hundreds dead.
That puts Britain’s relationship with the United States on the line, too: President Biden has made clear that Northern Ireland peace is a priority for him.
The issue is how to handle the border between Northern Ireland, which is part of the United Kingdom, and Ireland, part of the European Union.
Talks have been going on for months over issues like customs checks on chilled meats (the so-called “sausage wars”). Earlier this year it looked as if Britain’s foreign secretary, Liz Truss, was closing in on a deal, but the mood has shifted. Instead, Ms. Truss wants the power to junk parts of the set of trade rules negotiated for Northern Ireland, known as the Northern Ireland protocol, because Britain says they just aren’t working.
That’s not going down well in Brussels among diplomats, wearied by years of Brexit talks, who fear that Britain is preparing to break international law.
Here’s a guide to what’s going on.
What is the Northern Ireland protocol?
While the accord sounds like the title of a spy thriller, it’s actually a dry legal text that won’t be found on most people’s vacation reading lists.
The frontier between Northern Ireland and Ireland is contested, and parts of it were fortified during the decades of violence known as The Troubles. But customs checks ended after both Britain and Ireland joined the forerunner of the European Union, and other signs of division that remained along the open border have faded since the Good Friday peace deal of 1998.
No one wants checkpoints back, but as part of his Brexit plan, Mr. Johnson insisted on leaving Europe’s customs union and its single market, which allows goods to flow freely across European borders.
The protocol sets out a plan to deal with this situation. It does so by effectively leaving Northern Ireland half inside the European system (and its giant market), and half inside the British one. It sounds neat — until you try to make it work.
Why doesn’t Britain like it?
The plan means more checks on goods entering Northern Ireland from mainland Britain, effectively creating a border down the Irish Sea and dividing the United Kingdom. Some British companies have stopped supplying stores in Northern Ireland, blaming the added paperwork.
This has enraged some Conservative lawmakers and inflamed sentiment among those in Northern Ireland who want the region to remain part of the United Kingdom.
Some Brexit supporters also see the protocol as a means for the European Union to retain power over a part of their country — a suspicion reflected in Britain’s desire to remove any role in the region for the European Court of Justice, the bloc’s top court.
So while not being able to get the right kind of sausages might seem a small inconvenience, to many of Northern Ireland’s pro-British Protestants, it feels as if their identity is in the fryer.
Why is the E.U. insisting on it?
The bloc has dug in its heels, partly because Mr. Johnson not only accepted the protocol, but also negotiated it and pushed it through the British Parliament.
For critics of Mr. Johnson, the rift over the protocol is evidence of his lack of trustworthiness and his denial of responsibility for the consequences of the withdrawal from Europe he championed. Mr. Johnson’s allies accuse the European Union of inflexibility in applying rules, lack of sensitivity to feelings in parts of Northern Ireland and vengeful hostility toward Britain.
But E.U. leaders believe that the bloc’s existential interests are at risk. If Brussels can’t control what enters its single market, they argue, it could threaten the building blocks of European integration.
Does anyone like the protocol?
Yes. After recent elections in Northern Ireland, a majority of lawmakers there represent parties that want to keep it, albeit with some improvements. That’s because the protocol was designed to prevent the reintroduction of goods checks at the politically sensitive land border between Northern Ireland and Ireland.
A return of border checks would likely destabilize the peace process and particularly upset Sinn Fein, the biggest party after the recent election. As a party that campaigns for Irish unity, it is hostile to any structures that appear to divide the island.
Some companies in Northern Ireland also benefit from the protocol because it allows them sell their goods across Europe’s huge internal market as well as exporting to mainland Britain.
What about those sausages?
Under the protocol, foods with animal origins — yes, like sausages — coming from mainland Britain into Northern Ireland need health certification to ensure they meet European standards should they end up in Ireland.
The British want a light-touch system, with a new “green channel” and minimal checks on goods that companies promise will stay in Northern Ireland, while the European Union wants Britain to minimize the need for controls by signing up to Europe’s health certification rules. So far many of the regulations have been waived during a “grace period.” There was an uneasy truce in the sausage wars, with chilled meats still crossing the Irish Sea.
Last year Brussels offered concessions that it said would reduce checks on food and animal products by 80 percent, slash customs paperwork for shipments of many goods, and ensure the flow of medicines.
But Britain now says that plan makes the situation worse in some cases.
What would happen if Britain withdrew?
Britain says it has grounds already to deploy an emergency clause known as Article 16 that permits it to effectively suspend parts of the protocol. But Ms. Truss is instead proposing British legislation that would let her unilaterally override parts of the agreement.
If Britain does this, the European side would most likely accuse Mr. Johnson of breaking a treaty. This could strain the unity that the West has shown during the Ukraine conflict, which has brought the European Union and Britain closer together. It could also lead to a trade war. That is the last thing the British government needs, with inflation expected to surge to double digits.
Is this all just a negotiation tactic?
During the Brexit talks, Mr. Johnson often played hardball with the Europeans, sometimes relying on a so-called madman strategy and threatening to quit the bloc without any deal at all.
So this may just be another roll of the negotiating dice, and most analysts believe that, for the British, the best outcome would be winning concessions from Brussels.
But Northern Ireland’s internal politics may change the calculation. The region’s power-sharing government is in suspended animation because the pro-British Democratic Unionists, who finished second in the recent election, are refusing to take part. They say the protocol needs fundamental changes.
So far, the European Commission’s response has been to talk to business and other groups in Northern Ireland and to focus on resolving their practical problems.
So isn’t it risky?
Yes, because ultimately, Mr. Johnson has no real alternative to the protocol short of ripping it up and daring Ireland to resurrect the Irish border. That could inflame sectarian tensions in Northern Ireland, provoke a trade war with Brussels and heighten tension with the Biden administration.
Monika Pronczuk contributed reporting from Brussels.