Orange Order march row goes to heart of ongoing divisions in Northern Ireland

History shows that when the politics of Northern Ireland are wrapped up in a street dispute, friction is seldom far away.

Bitter rows in the Stormont chamber between unionists and nationalists happen almost every week, but ground-level arguments are rare these days.

The Drumcree parade dispute in Portadown is a clash of political cultures.

The Orange Order is a Protestant pro-British organisation. The area where it wants to walk is largely Catholic, and predominantly inhabited by pro-Irish nationalists.

This dispute over a piece of road is not just a local problem. It has the potential to affect other parts of Northern Ireland and the power-sharing arrangements at Stormont.

"What happens at Drumcree never stays at Drumcree," was how one retired politician put it.

When the parade dispute first erupted into violence in the mid-1990s, the disorder spread to other places - and almost derailed the peace process.

But while it was never fully resolved, the dispute faded over the next 30 years. Its sudden re-emergence has caught most people by surprise, including many politicians.

What happened was that a legal case was brought to court over the dispute early this summer, re-opening the debate.

The two largest parties in Northern Ireland, Sinn Féin and the Democratic Unionist Party (DUP), have been on opposite sides of the argument.

Sinn Féin are firmly behind the residents. The DUP fully supports the Orange Order.

They may be partners in the devolved government at Stormont, but when it comes to Drumcree they could not be further apart.

As always in Northern Ireland, the historical context is important.

Although there has been an uneasy calm in Portadown over the parading issue in recent years, the Orange Order regards the march as unfinished business.

In 1998, it was banned from completing its Drumcree march - which includes the Garvaghy Road - and has been repeatedly refused permission to finish the route ever since.

It has applied and been turned down more than 1,000 times in the past three decades.

It says it is being denied a traditional walk which dates back to the early 1800s.

A Parades Commission was set up in the late 1990s to adjudicate on marching disputes and, until now, it has consistently ruled against the route.

The Orange Order's legal challenge to a ruling in June this year succeeded on procedural grounds.

The order subsequently re-applied for permission to carry out the parade, albeit a scaled-back version with only 35 participants rather than 400 - and was successful.

Nationalist residents on the Garvaghy Road were left shocked and angry.

For them, the parade is triumphalist and unwelcome in the area.

Rather than being about tradition, they see the parade as an act of supremacy and say it re-opens old community wounds.

During a last-minute legal battle over the march, a judge appealed for all sides of the dispute to find common ground and come to an agreement.

Nobody was surprised when that did not happen.

Feelings are running high on the issue on all sides, including among the political parties.

Relations in the power-sharing executive are now dangerously close to breaking point.

There is a Stormont election next year which means parties tend to dig in, rather than search for compromises.

The Drumcree dispute goes to the heart of the divisions which remain in Northern Ireland.

Events of recent days are a reminder that the peace process is not over, it is ongoing - and there is still work to be done on the ground and at Stormont.