While we looked the other way - at a world that is melting, free-falling into depression, and warring over the remaining resources - the dreary steeples were there, waiting for us. After the First World War, Winston Churchill wrote: "Every institution in the world was strained. Great Empires have been overturned. The whole map of Europe has been changed... But as the deluge subsides and the waters fall short, we see the dreary steeples of Fermaagh and Tyrone emerging once again. The integrity of their quarrel is one of the few institutions that has been unaltered in the cataclysm which has swept the world."
Now we are waiting, hunched, for Protestant paramilitaries to retaliate, or the Continuity IRA to launch another atrocity. Back to the future. After the flurry of resurrected hope on Good Friday, there a low sense of: is this it? Are we stuck watching this nasty little movie forever?
We aren't. Everybody has written about the amazing unity shown by the Northern Irish political class in urging people to hand in the murderers. Even Gerry Kelley - who bombed the Old Bailey in 1973 - issued a tender, plangent plea for Catholics with information to come forward. The world can change; it can get better.
But there is another dimension to this story that has been unmentioned this week - and offers the greatest hope of all. If we take the energy from the peace marches and plough it here, into this, we can dismantle those dreary spires at last. If we lose the opportunity, we will - over time - set up more generations of sectarian senselessness.
The Good Friday Process has - from the beginning - been focused on the small elite of politicians at the top. Ian Paisley and Martin McGuiness have been sitting together - inspirationally - but in the streets and estates beyond Stormont, Northern Irlenad has been becoming even more divided. Dr Peter Shirlow, of the University of Ulster, has conducted the most detailed survey of inter-communal relations in Northern Ireland - and found an almost completely segregated society. Only 5 per cent of the workforce in Catholic areas are Protestants, and vice versa. Some 68 per cent of 18 to 25-year-olds had never had a meaningful conversation with a single person from "the other side". The young are more likely to fear and hate the "Prods" or "Taigs" than any other group. We have been fixing the ceiling, while the foundations fracture.
You can see this when you visit Belfast or Derry. To a British person, they feel like any familiar CloneZone town - except they are layered with a strange hatred you cannot grasp. Taxis will either take you to green or orange areas - never both. Even the KFC is covered with a mural memorialising a centuries-old battle. The cities are sliced by vast 40ft tall steel walls, keeping Catholics and Protestants apart. And there are more of them now than ever before. Talk to the kids, and they will gleefully tell you the other side stink, or are stupid, or lazy. We are currently spending £1.5bn a year keeping the two sides physically apart.
But here's the good news: there is a proven, tested way out. There is a policy that has been shown over time to dissolve these hatreds. They are called integrated schools - and the parents of Northern Ireland are calling for them. Today, only 5 percent of children in Northern Ireland go to a mixed school. The other 95 percent are segregated in sectarian enclaves where they project feverish fantasies onto the other side. Violence becomes an inevitable bedsore where two uncomprehending tribes rub past each other in a small space.
But that 5 percent hold the key. A major six-year study by Queen's University, Belfast has looked at the long-term consequences of being schooled alongside The Enemy. They interviewed adults who attended these schools - and found that whatever their parents' attitudes, they were "significantly more likely" to oppose sectarianism. They had more friends across the divide, and they identified as "Northern Irish", rather than British or Irish. Their politics were far more amenable to peace: Some 80 percent of Protestants favour the union with Britain, but only 65 percent of those at integrated schools do. Some 51 percent of Catholics who went to a segregated school want unification with Ireland, but only 35 percent of those from integrated schools do. The middle ground - for a devolved Northern Ireland with links to both countries, within the EU - was fatter and happier.
It's difficult to caricature people you've known since you were a child: great sweeping hatreds are dissolved by the grey complexity of individual human beings. Think of the young lads who, as you read this, are being persuaded by the Continuity IRA and the Ulster Defence Force to sign up and take on The Others. If they had grown up with crushes on Catholic girls they sat next to in Geography, or playing football with Protestant boys at break-time, wouldn't they be more likely to question the demonisation they're being fed and find a way to live together?
But there is better news still. In the most detailed study of Northern Irish opinion, an extraordinary 82 percent said they personally support the idea of integrated schooling, and 55 percent of parents say the only reason their kids don't go to an integrated school is because there isn't one in their area, or they can't obtain a place. There is a huge pent-up demand in the province for the very mechanism that will - over time - provide peace from the bottom up.
So why isn't it happening? Small minorities of religious sectarians - both Protestant and Catholic - have been allowed to dominate the school system. The respective churches have deliberately obstructed integrated schools, refusing to nominate people to sit on their boards, and jealously guarding their profitable privileges. Northern Ireland needs its own equivalent to Brown vs, the Board of Education, the 1954 Supreme Court judgement that desegregated the schools in the Deep South. The church hierarchies will be left yelling, like Governor George Wallace of Alabama, "Segregation today, segregation tomorrow, segregation forever" - and shamed before the world.
There are brave forces within Northern Ireland fighting for this to happen. David Montgomery - chair of the Integrated Charter for Choice Campaign - says that Northern Ireland's children are being "deprived of the basic right to share each other's company because of rigidly segregated education. In later life, more and more of us have grown to deeply resent this system that has robbed us of friendships and the chance to experience and understand the other side's culture and community."
There is a neat historical coincidence that this call comes at the moment when Northern Ireland's school-age population is contracting - and many schools will have to merge anyway. There is currently a surplus of 50,000 excess school paces in the province, and it's set to balloon even further as the birth-rate falls. Schools should be folded together into integrated wholes. All new schools should be mixed by law.
The British and Irish governments can launch a Phase Two of the Good Friday Agreement now, setting ambitious targets for integrated schools to rapidly expand. Martin Luther King didn't dream of a little black boy and a little black girl playing in separate playgrounds, with a vast steel wall between them. No. Our leaders can offer a Northern Ireland where Catholics and Protestants will play together and, in time, have kids together, the most shining symbol of coming together. Who knows - a hefty push for school integration could yield, in a few decades, a Northern Irish Obama, carrying both sides in his veins.
The blood-spilling of the past week - and the rock-solid resistance to it - should lead us to a new political cry. Prime Minister Brown, Taoiseach Cowen, First Minister Robinson - tear down this wall between Northern Ireland's children.