WHEN the Irish Republican Army at last put aside its weapons, ending a century-long insurgency against the British state, witnesses were needed to confirm that the guns were gone for good. Two clergymen were chosen, Harold Good, a Protestant, and Alec Reid, a Catholic. As they travelled in secret between rural arms-dumps with the IRA’s quartermasters and an international team of weapons decommissioners, they noticed a young IRA man with an old-fashioned rifle among the group. When the last of the arsenal had been destroyed, the young man marched up to the general in charge, clicked his heels and solemnly handed over his gun. Now in his 80s, Reverend Good recalls the moment: “Father Reid said to me, ‘There goes the last weapon out of Irish politics.’ We just fell silent.”

Northern Ireland’s long war ended with the Belfast Agreement, signed on Good Friday in 1998. The deal between the governments of Britain and Ireland, in conjunction with the main Northern Irish parties and the paramilitaries some of them spoke for, spun a delicate web of compromises between the province’s Protestants, most of whom want to remain in the United Kingdom, and its Catholics, who more often identify with the Republic of Ireland. The “Troubles” of the previous 30 years—the most recent spasm in a conflict dating back to Britain’s planting of Protestant settlers in the 17th century—caused the deaths of more than 3,500 people, mostly civilians. Tony Blair, then Britain’s prime minister, later described signing the deal as “one of the few times in the job I can honestly say I felt contented, fulfilled and proud.”

Yet 20 years on, the mood is sour. In Belfast the Stormont assembly has lain empty for over a year. The British and Irish governments have warned that commemorations of the agreement will feel “hollow”. The two countries are publicly bickering over Northern Ireland’s fate after Britain leaves the European Union next year. Vexed questions that the Good Friday Agreement had carefully put aside—on borders, identity and to whom Northern Ireland really belongs—are dangerously back in play.

Changed utterly

Under the agreement Ireland gave up its claim on the north and Britain agreed to a mechanism by which Northern Ireland could secede via a future referendum. The Northern Irish gained the right to citizenship of the United Kingdom, Ireland, or both. International bodies were set up to give the two countries shared oversight of how the place was run. And a devolved government was established at Stormont, one in which nationalists and unionists would share power. Paramilitaries who had dealt in Semtex and Armalites turned their attention to early-day motions and the d’Hondt voting system.

Security has been transformed. In 1972, the bloodiest year of the Troubles, 498 people were killed in sectarian violence. As recently as the early 1990s the annual death toll was around 100. Now it is in the low single digits. Northern Ireland’s murder rate is equal to the British average, its overall crime rate slightly lower. Sectarian hate-crimes have fallen by more than half since 2005, when they started being recorded. Belfast feels like a normal European city. Crumlin Road prison, once a holding place for paramilitaries, is now a tourist attraction that hosts weddings (promising, and doubtless providing, “a surrounding that will keep your guests talking”).

Yet not all the past is so deeply buried. The police detect the “continuing existence and cohesion” of an IRA hierarchy, though they accept that the organisation is now committed to a political path. So-called dissident republican gangs continue to fight a lonely war against the British state, foiled most of the time by the police and MI5, Britain’s security service, which still devotes about 15% of its energies to Northern Ireland.

Paramilitary gangs on both sides of the sectarian divide are active in organised crime. Their “punishment” beatings and shootings of drug-dealers, pimps and loan-sharks purport to be for the protection of “their” communities, but often they simply want the business for themselves. Some former paramilitaries have been prosecuted, others have been co-opted. The hardest ones to deal with, says George Hamilton, the chief constable, are those in the murky middle ground, who “want to be community workers by day and paramilitary thugs by night”.

Such organisations live on because Northern Irish society is still divided. Physical walls, known as peace lines, still separate some working-class Catholic and Protestant areas. Indeed, more have been built since 1998, because they are popular. “I wouldn’t like it down,” says a resident of Bombay Street, a Catholic district in Belfast separated from Protestant Shankill by a ten-metre-high wall. “They’re lovely people. It’s just the lunatics.” The wall has been made higher several times since it was erected in 1969. Stones still sail over, so houses nearby have metal cages over their back gardens.

Devout and profane and hard

Surveys show that three-quarters of people would like to live in integrated neighbourhoods, and two-thirds would send their children to mixed schools. Yet making this happen has proved difficult. A handful of mixed social-housing developments have been started, but the “lunatics” make them dicey places to live. Last year four Catholic families in a mixed-housing project in Cantrell Close, Belfast, were advised by police to leave, after threats from paramilitaries. The share of children in formally integrated schools has edged up only slightly since 2000—from 3% to 5.8% in primary and from 5.6% to 8.6% in secondary—partly because of opposition from the Catholic church, which runs many schools of its own. The province remains astonishingly segregated (see map).

In other areas there has been progress. Integration has deepened in the workplace, helped by laws compelling big firms to publish the religious breakdown of their staff. Catholics hold nearly half the jobs in both the public and private sectors, in line with their share of the population. A once-yawning unemployment gap has nearly closed. Catholics hold high-profile public offices, including those of attorney-general and Lord Chief Justice. Their share of police officers has risen from one in ten at the turn of the century to one in three, after a temporary affirmative-action programme.

National and religious identities are blurring, particularly among the young. A Protestant minister says he now christens more children with Irish names like Una, Malachi and Sadhbh. Many young Catholics have little interest in Ireland, which some refer to as “Mexico”. “I’d rather go to Spain or something, to tell you the truth,” says Martin, a 29-year-old who lives near the Falls Road in Belfast. Surveys find that about a third of the population considers itself British, a slightly smaller share says Irish, and around the same reports itself to be neither, but rather Northern Irish.

This nuanced, cautiously evolving identity is lost in a local politics that is crudely sectarian, and becoming grimly more so. At the time of the agreement the main forces in Northern Irish politics were the Ulster Unionists and the Social Democratic and Labour Party (SDLP), which represented the moderate forms of unionism and nationalism, respectively. Those two parties have since been swept aside by the harder-line Democratic Unionist Party (DUP) and Sinn Fein, the former political wing of the IRA and the only party that stands at elections both in Northern Ireland and the Republic. Whereas in 1997 the region’s 18 Westminster seats were split between five parties, in last year’s general election the DUP and Sinn Fein took all but one. They have also come to dominate the devolved assembly and executive.

In January last year a long-simmering row between the two parties blew up and Sinn Fein walked out; without its participation, the institutions cannot function. Fourteen months without a government have proved trying. The budget has been delayed, laws to reorganise health care and tackle domestic abuse have been put on ice, public-sector pay rises have not been honoured, and institutions such as the policing board, which holds the police accountable, have been unable to fulfil their functions. Negotiators predict that it will be months before the two parties work together again.

That such an impasse can persist is in part due to the design of the Good Friday Agreement, which intentionally provided a plethora of constitutional vetoes to protect each side against the other. The ability of either main party to collapse the executive by walking out makes for unstable, high-stakes government. The agreement has fostered a structural divide in other ways, too. A supermajority required for legislation that could threaten one community has been cynically used by both sides to block measures they merely dislike. Parties must declare themselves followers of one of the “two traditions” (they may register as neither, but then lose some voting rights).

Paul Nolan, a Belfast-based researcher, compares the polarisation to a seesaw: whenever one party has moved farther from the centre, the other has done the same to balance it. Seeing the other side as ever more extreme, voters feel they have little choice but to vote for their own lot of extremists. As one assembly member puts it: “If they’re going to elect an arse, we’re going to elect an arse.”

When the Stormont government has run aground before, Britain and Ireland have stepped in to get it back afloat. But Britain’s role as a referee has been impeded by a deal last year between the Conservatives and the DUP, which agreed to support Theresa May’s minority government in Westminster on important votes in return for £1bn ($1.4bn) of extra money for Northern Ireland. The alliance “undermines a tradition of neutrality going back to at least 1990,” says Jonathan Powell, who as Mr Blair’s chief of staff helped to negotiate the Good Friday Agreement.

Gathering Stormont

To get Stormont back up and running, Ireland has called for a meeting of the agreement’s British-Irish Intergovernmental Conference—which could be chaired either by Ireland’s foreign minister and Britain’s Northern Ireland secretary, or by Mrs May and Leo Varadkar, the Irish taoiseach. Britain has not taken up the offer (an official says Ireland has not issued a formal request). The DUP is opposed to it. “The British government needs to remove the blocks. But it’s tied to the DUP,” says Gerry Kelly, a Sinn Fein assemblyman.

What is more, Mrs May and Mr Varadkar have another matter on their minds: Brexit. In 1998 Britain and Ireland were, in the words of the Good Friday Agreement, “partners in the European Union”. On March 29th 2019 that will cease to be the case. In 2016 the High Court in Belfast ruled that Brexit would not formally invalidate the agreement, as some had argued. But it will complicate the relationship hugely.

Britain and Ireland have identified 142 areas of cross-border co-operation. Combined cancer services, a single wholesale power market and police intelligence-sharing give an idea of the range. Officials reckon most of this can more or less continue, though it will involve mountains of work—but regret that future initiatives will be harder to get started. Northern Ireland has received a lot of EU money, via initiatives such as Peace IV, worth €270m ($335m) in 2014-20. Unlike funding from Britain (tainted in the eyes of some Catholics) or America (long involved in the peace process, but seen as leaning towards the nationalists by some Protestants), EU grants are viewed as neutral. The EU has indicated that some funding can continue after Brexit.

The biggest problem concerns the border, around which Mrs May has drawn three negotiating “red lines” that seem to run into each other. She insists that Britain will leave the EU’s customs union and single market. Yet she also promises there will be no new customs checks or physical infrastructure at the Irish border, or any between Northern Ireland and Britain.

The government argues that trusted-trader schemes, waivers for small firms and unspecified technology could let customs checks be carried out invisibly. So far the EU is not convinced. Some member states are unwilling to turn a blind eye even to trade by small businesses. And no one, including the Northern Ireland committee of Britain’s Parliament, has yet identified technology that could enforce customs controls without any infrastructure.

Borderline disorder

The opposition Labour Party backs membership of a customs union, as do a handful of Tory rebels. Mrs May said in February that she was open to a customs “arrangement”, which could amount to something very similar. Yet Jacob Rees-Mogg, who speaks for an influential caucus of Eurosceptic Tories, has said that the right to set tariffs, possible only outside a customs union, is “non-negotiable”. And it is not clear that membership of a customs union alone would be enough to maintain the invisible border, anyway. If Britain leaves the single market and diverges from EU regulatory standards, goods crossing the border would need to be checked.

The idea of such inspections is neuralgic for those who live near the frontier. Conor Patterson, head of the Newry and Mourne Enterprise Agency in South Armagh, remembers when Newry last had a customs post. It was blown up in 1972, killing nine people. His father required a triangular badge from the police to cross the border, something which could take an hour at busy times. British soldiers would sprint through the streets of Newry, for fear of snipers. Nearby Bessbrook was home to the busiest heliport in Europe, operated by the British army. The local roads were so dangerous that it had to fly men and supplies around the 18 nearby watchtowers.

No one foresees a return to those conditions. But David Davis, Britain’s Brexit secretary, betrays a deep and complacent misunderstanding of the problem when he breezily suggests that the frontier could resemble that between America and Canada. “It’s not a question of the speed of the lorries crossing the border. It’s the question of identity,” says Mr Powell. To win support for the 1998 agreement, nationalist leaders in both north and south needed to show tangible benefits. None was clearer than dismantling the border. A Canada-style crossing, one with “people in uniforms with arms and dogs”, is “not a solution [Ireland] can possibly entertain”, Mr Varadkar said on March 5th.

The security services are aware of the risks. “We would have a responsibility to have a presence there,” says Mr Hamilton. In policing terms, “any physical infrastructure or control measures that required people to be physically at the border would be a very bad thing…It would be perceived as being a symbol of the British state.” Dissident republican paramilitaries, who have almost no public support for their cold-blooded attacks on police, might win wider backing for strikes on border installations. Resentment at a return to a hard border could provide the “sea” of public sympathy that Mao Zedong said terrorists need to swim in, fears Brian Feeney, a former SDLP councillor.

Nor would the EU’s suggested “backstop” of a customs border between Northern Ireland and Britain be easy to swallow. “People would absolutely resist any attempt to cordon off” the province from the mainland, says Winston Irvine, a Shankill community leader who is familiar with the thinking of west Belfast’s paramilitaries. Unionist protests have flared over far smaller affronts to British identity. A decision in 2012 to reduce the days on which the union flag would fly at Belfast City Hall triggered a year of protests in which 150 police officers were injured and a political party’s office firebombed. “People are getting a bit twitchy about where all this is going to land,” says Mr Irvine.

The mood of reanimated Irish nationalism and unionist mistrust of the British government is “all rather redolent of 1920”, notes Diarmaid Ferriter, a historian at University College Dublin. Then, Northern Ireland was separated from the south, ahead of the creation of the Irish Free State. Now, he says, “Brexit has thrown the issue of the unity of Ireland back into the frame.”

Taking back control

No one was surprised when Sinn Fein demanded a unification referendum a few days after the Brexit vote. Less expected have been the shifts in thinking among moderate nationalists. “If we’re at constitutional ground zero then absolutely, we’re going to start looking at the north-south question,” says Claire Hanna, an SDLP member of the assembly. In December Simon Coveney, Ireland’s foreign minister, said he hoped to see a united Ireland “within my political lifetime”. He is 45.

Building walls as well as bridges

Could it happen? Northern Ireland’s Catholics will soon outnumber its Protestants. In March 2017 Sinn Fein came within 2,000 votes of outpolling the DUP in elections to the assembly. Not all the party’s supporters, let alone all Catholics, would vote for unification. A poll in 2015 found that 30% of Northern Irish would be in favour—and when respondents were told that it would mean higher taxes (a near certainty, as Ireland could not afford the £10bn of subsidies that Britain shovels to Northern Ireland each year), the figure dropped to 11%. Support in Ireland dropped from 66% to 31% when the financial implications were pointed out.

It remains to be seen how much Brexit will move those figures. But at a time when populist nationalism is on the rise around the world, matters of culture and identity can sometimes count for more than economic self-interest. Whatever else they misjudge about Ireland, Brexiteers, of all people, should understand that.