LONDON — Rarely have Britain’s politics looked so shambolic: a revolving door of prime ministers in Downing Street; the sudden resignation of Scotland’s formidable longtime leader, Nicola Sturgeon; and the lack of a functioning government in Northern Ireland.
Yet beyond the disarray, there are the glimmerings of a path to a more stable United Kingdom.
On Friday, the current prime minister, Rishi Sunak, met with pro-unionist leaders in Northern Ireland’s capital, Belfast, to enlist their support for an agreement with the European Union on post-Brexit trade arrangements in the territory. That has buoyed hopes that Mr. Sunak could present the deal to the British Parliament as early as next week.
If the prime minister is able to secure a deal — a big if — it could open the door to restoring the power-sharing government in Belfast. And that, in turn, could quiet the voices of those calling for Northern Ireland to break away from Britain and unite with the Irish Republic.
“If the protocol can be made to work, it would be very good for Northern Ireland,” said Bobby McDonagh, who served as Ireland’s ambassador to Britain, referring to the Northern Ireland Protocol, which governs trade between the North and the E.U. “If it doesn’t work, and if there were some sort of border erected on the island of Ireland, nothing could do more to reignite a debate about Irish unity.”
In Scotland, the departure of Ms. Sturgeon, a clarion voice for Scottish independence, has left that movement at loose ends. Not only does it lack a leader as commanding as her, but it also lacks a clear path to independence — one of the reasons that Ms. Sturgeon chose to step down after eight years as first minister.
Nobody expects the Scots to give up their dreams of independence, just as nobody expects Irish nationalists to give up their goal of a united Ireland. But taken together, Mr. Sunak’s high-stakes diplomacy with Belfast and Brussels, and Ms. Sturgeon’s abrupt departure in Edinburgh, could slow the centrifugal forces that have threatened to unravel the United Kingdom in the aftermath of Brexit.
“Sunak is trying to put the pieces of the jigsaw puzzle back together,” Mr. McDonagh said. “He’s doing his best to restore some sanity to British politics, but we don’t know whether he’ll have the strength to carry this through.”
Some of it is out of his hands: the Scottish National Party will choose a new leader in the coming weeks, and the charisma and leadership abilities of that person will be critical to the fate of the independence movement.
On Northern Ireland, Mr. Sunak faces obstacles from pro-unionist leaders in Belfast, who seek to maintain political links with Britain, as well as from his own lawmakers in London. The Democratic Unionist Party, or D.U.P., is demanding that Britain effectively scrap the protocol, which gives the North hybrid trade status as a part of the United Kingdom that has an open border with the Irish Republic, a member of the European Union.
An even bigger threat could come from the pro-Brexit wing of the Conservative Party. Some of those lawmakers have threatened to oppose any agreement that would leave the European Court of Justice with jurisdiction over Northern Ireland. They argue that the court, which guarantees that European law is applied in all member states, infringes British sovereignty.
Though details of a potential deal remain closely guarded, analysts and diplomats said they appeared to distance, if not eliminate, the role of the European court by prioritizing other mechanisms to resolve legal disputes.
More tangibly, it seeks to remove paperwork and other barriers to goods flowing from mainland Britain to Northern Ireland. Unionists complain that these barriers drive a wedge between them and the rest of the United Kingdom. Under the terms being discussed, food and other goods destined for shelves in the North would pass through a “green lane,” requiring no customs declarations.
Whether these compromises would pass muster with the unionists was still unclear. On Friday, after meeting with Mr. Sunak, the leader of the Democratic Unionists, Jeffrey Donaldson, said, “progress has been made across a range of areas, but there are still some areas where further work is required.”
Even if the unionists accept the deal, analysts cautioned that they might not agree to go back into Northern Ireland’s power-sharing government. That is in part because Sinn Fein, the Irish nationalist party, is now the biggest party in the North’s assembly, which gives it the right to name a first minister.
The creation of that government was a key achievement of the 1998 Good Friday Agreement, which ended decades of sectarian bloodshed in Northern Ireland. Restoring the government, experts said, was important not just to improve daily life in the North but also to prevent sectarian tensions from resurfacing.
“When the government institutions don’t function, you see a rise in support for Irish unification,” said Katy Hayward, a professor of politics at Queen’s University in Belfast. “When they are functioning, you see a decline in support.”
Beyond Northern Ireland’s domestic politics, Professor Hayward said Mr. Sunak’s effort to reset Britain’s relationship with the European Union was critical to tamping down separatist passions in both the North and Scotland.
The Scottish independence movement was galvanized by Brexit, which was unpopular in Scotland as well as in Northern Ireland. The regular tiffs between Mr. Sunak’s predecessor, Boris Johnson, and European leaders like President Emmanuel Macron of France played better in England than they did in Scotland or Northern Ireland.
“Those tensions create a space that unionists and nationalists can fill,” Professor Hayward said. “If it’s possible to bring back certainly and stability in the U.K.-E.U. relationship, that will help calm the waters within the U.K.”
Mr. Sunak plans a weekend diplomatic blitz to seal the deal with Brussels. He is scheduled to meet with Ursula von der Leyen, the president of the European Commission, and other European leaders at the Munich security conference. He may also meet there with Vice President Kamala Harris and speak by phone with President Biden, who has urged Britain to settle its differences with the European Union.
Mr. Biden hopes to visit Belfast in April to celebrate the 25th anniversary of the Good Friday Agreement. A stopover in London could hinge on whether Mr. Sunak is able to secure an agreement by then. Mr. Sunak told Mr. Biden last November that his goal was to deliver it before the anniversary.
For Mr. Sunak, it is perhaps his stiffest test yet. Having replaced the scandal-scarred Mr. Johnson and the ill-fated Liz Truss, he has a tenuous grip over a divided party. Among the fears of his allies is an 11th-hour intervention by Mr. Johnson, who made the Brexit deal that Mr. Sunak is trying to overhaul and could mobilize opponents in London and Belfast.
“If he gets an agreement on the protocol, we’re going to be over the hump with the E.U. but not necessarily with the D.U.P.,” said Jonathan Powell, who was involved in negotiating the Good Friday Agreement as chief of staff to Prime Minister Tony Blair.
Regardless, Mr. Powell said, “We’re approaching a period of transition in British politics. You get these inflection points when things change a lot.”