Two weeks ago I was on the outskirts of Derry, a town in Northern Ireland, just a few yards away from the border where Britain ends and the Republic of Ireland begins. Behind a garden wall, a wiry, older man was eager to vent.
“This is Ireland! The English have no business here,” he exclaimed. He pointed down the road toward a small stone bridge. The checkpoint there vanished two decades ago, he said. Should the British try to erect a new guard house, he went on, “we will burn it down.”
Come on, I cajoled him, incredulously. What will really happen if, after Britain leaves the European Union, customs officers or the police might be stationed at what will then be a new border?
“We will stone them,” the man replied, more calmly. He shrugged, warming to his idea. “Yeah. We’ll stone them.”
There is no end to the problems surrounding Brexit, but especially for the rest of us Europeans, the dilemma at the Irish-British land border is the most perplexing, and perhaps the most concerning, at least in a symbolic sense. This week Chancellor Angela Merkel is traveling to Ireland to see firsthand what is happening.
Europe in the 20th century was marked by hideous violence — often wars, but just as often extended periods of political violence, like the Troubles in Northern Ireland. The great postwar project of European cooperation and unification was an effort to, among other things, make that violence a thing of the past. The Good Friday Agreement, which brought the Troubles to an end, seemed to validate everything we had worked toward, whether “we” were Irish or British or German.
Now, with Brexit looming, the talk of renewed violence in Ireland brings that optimism and progress into question.
Whether the Troubles are about to return is still just speculation. But in Ireland, many people believe it. “If there is going to be hard borders in Ireland,” Richard O’Rawe, who showed me around that day, said, “there will most definitely be a flare-up of violence, both in the short and long term.”
Mr. O’Rawe knows what he is talking about. In the 1970s, at the height of the Troubles, he belonged to the Irish Republican Army. He was imprisoned by the British; in prison he served as spokesman for a group of inmates associated with the political activist Bobby Sands, who died after a hunger strike in 1981. After prison, Mr. O’Rawe wrote several books on the conflict and broke with the I.R.A.
Twenty years have passed since the Good Friday Agreement. To a German visiting Northern Ireland, a couple of similarities with my own country, reunited 30 years ago, spring to mind. Social cleavages have softened but not vanished. A heavily protected barrier that once was a symbol of unnatural separation has given way to a natural coalescence.
But unlike in Germany, the former oppressor is still a political player in Northern Ireland. Germany has its regional differences, but there is no doubt that we are all Germans. Not so on the island, where resentment at what is seen as English highhandedness runs rife — and where few believe that things will be any better post-Brexit.
Mr. O’Rawe worried that a new, visible dividing line on the island would revive ancient division and anger. “A hard border would cement the injustice that has been historically perpetrated against the Irish people,” he said. “It would be presented as the British government asserting a warped definition of democracy in Ireland to suit their own agenda, and would energize the adage that Britain only respects one thing: the barrel of a gun.”
In the 2016 Brexit referendum, a majority of people in Northern Ireland, 55.8 percent, voted to remain in the European Union. This means that it would be dragged out of the union against its will, and in particular against the will of its Irish nationalists. Support for independence, and a reunification with the Irish republic, is growing.
In London, Prime Minister Theresa May has vowed to respect the peace accord and avoid a hard border in Ireland. But neither she nor anyone else has yet explained how not to control a border that separates a European Union country from a nonunion country. Mrs. May’s Brexit plan leaves open the possibility of at least customs checks along the border; without a plan in place, a hard border will almost certainly be needed.
Mr. O’Rawe believes that the British government, preoccupied with political strife in Westminster, has given no thought to what Brexit might bring in terms of violent Republican reaction. “They see a weak dissident campaign at present,” he said, “and tell themselves that they’ve nothing to worry about. But they are blinkered fools.”
In January, just a few miles from were I met the angry local man, a car bomb exploded in the center of Derry. No one was injured, luckily, but the entire island was unnerved. The police blame a splinter group called the New I.R.A.
Though the I.R.A. is a small shell of its old self, some suspect that it is eager to see a hard border, and the strife that would accompany it. Martin McAllister, an ex-I.R.A. member I met in South Armagh, said he also quit the organization in the 1970s, when he decided it had devolved into a terrorist criminal enterprise. A few years ago, after he began speaking out about I.R.A. gangsterism, he was ambushed and beaten.
Driving through his home region, Mr. McAllister pointed out a remarkable number of oil tanks and fuel trucks — the sign, he said, of a gasoline-smuggling ring, a continuing activity left over from the Troubles.
“For the I.R.A., this was a way of making money to pursue the war,” he said. “Some of the main leadership of the I.R.A. have been personally involved in it for personal gain.” Profits are lower today, but a border will change that. “If there is a hard border, all these smugglers will have a great time.”
If you believe Mr. McAllister and Mr. O’Rawe, a hard border across the island will effectively be a tripwire. Locals will loathe it. Gangsters will love it. And ultimately, a generation of new resistance fighters might find themselves in a conflict of interest with Godfathers-turned-freedom fighters.
A whole generation of Europeans has grown up seeing Britain as a nation that overcame its bitter sectional differences — proof that cooperation worked, that borders might be a thing of the past. Now not only is Britain turning its back on Europe, but it is also turning its back on one of the signal achievements of the European idea. The ramifications of that decision will reach far beyond Derry and South Armagh.
Jochen Bittner is a political editor for the weekly newspaper Die Zeit and a contributing opinion writer.