BELFAST — Northern Ireland has long been a place apart in U.K. politics. The major British parties rarely contest elections there and for almost a century, political life in this territory of some 1.5 million has been dominated by rival nationalist and unionist blocs — and, often, the specter of violence.

There are few starker examples of this political isolation than the Northern Irish Assembly, which has power over a range of policy areas. All assembly members must designate themselves “nationalist,” “unionist,” or “other.” Most bills require 60 percent support to pass and at least 40 percent support from both the nationalist and unionist designations.

The administrative branch of the Assembly — the Northern Ireland Executive housed at Stormont, outside Belfast — has always been governed by mandatory coalition: The five largest parties have shared power under a system created to manage tensions between nationalists and unionists.

The result has been electoral stasis. Earlier this month, the Democratic Unionist Party and Sinn Fein, the former political wing of the Irish Republican Army (IRA), once again finished first and second, respectively, in assembly elections.

"It doesn’t matter who you vote for, they all get in,” has long been a refrain on both sides of the corrugated iron "peace walls" that divide largely Catholic nationalists and Protestant unionists in parts of Belfast.

But Northern Irish politics is finally showing signs of change.

As of this week, Northern Ireland's power-sharing Executive has a significant opposition for the first time since the Good Friday peace agreement was signed in 1998. The move comes after both the smaller nationalist and unionist parties, the Social Democratic and Labour Party (SDLP) and the Ulster Unionists, as well as the cross-community Alliance, decided not to take up their ministerial seats when the parliament reconvened on Wednesday.

Under Northern Ireland’s complicated electoral system both the Ulster Unionists and the SDLP are entitled to one ministry each based on the seats they won in elections on May 5, but both parties have chosen to voluntarily sit on the opposition benches.

“This is a big and bold move to bring a better and more normal democracy to the people of Northern Ireland. Let battle commence,” said Ulster Unionist leader Mike Nesbitt, a former television news presenter. Colum Eastwood, 33-year-old leader of the nationalist SDLP, said his party had made a “bold decision."

"This is a very important day not just for the SDLP, but for politics generally," Eastwood said. "We know that nationalism spent decades in opposition and it's not a place that we go to easily but we also know that it's time for a change in our politics."

Almost two decades on from the end of the Troubles — the name given to the 30-year-long conflict that cost more than 3,000 lives — Northern Ireland is ready for a more normal form of politics, said Jonny Byrne, lecturer in politics and social policy at the University of Ulster.

“Eighteen years after the Good Friday Agreement it is about time that we decided to stand on our feet and make difficult decisions,” said Byrne. “In the past everyone was in the Executive. There was comfort in cross-party support. Now that cross-party support won’t be there anymore.”

Veteran unionist political commentator and former director of communications for the Ulster Unionists, Alex Kane, said opposition politics could improve government accountability.

“You can’t have accountability when 102 of the 108 MLAs (members of the local assembly) are connected to executive parties,” said Kane. A recent analysis found that the outgoing Stormont administration failed to deliver on nearly half of its policy pledges.

“Now it will be ministers and shadow ministers. That will change the political dynamic. Then you can have a debate instead of what we have had until now, which is ministers arguing over nonsense and nobody expecting a decision. The government can’t hide any longer.”

With 66 of the assembly’s 108 seats between them, the Democratic Unionist Party (DUP) and Sinn Fein have a comfortable majority. Nevertheless, the decision to create an opposition has taken both parties’ leadership by surprise.

“It came as a huge shock to Arlene (Foster of the DUP, who took over as first minister of Northern Ireland in January) and Martin (McGuinness, Sinn Fein's deputy first minister) when the Ulster Unionists and the SDLP chose to go into opposition,” said Kane.

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The move to opposition politics is not entirely altruistic. Both the SDLP and the Ulster Unionists — the moderate arms of nationalism and unionism — have hemorrhaged support to the more hardline DUP and Sinn Fein.

In the first assembly election in 1998, the Ulster Unionists and the SDLP topped the poll; this month the Ulster Unionists won the lowest share of the vote in its history while the SDLP limped home with 12 seats, just one more than the minimum required to pick up a ministerial post. Alliance, which draws support from across the sectarian divide, remained stuck on eight seats.

“They looked at those figures and thought ‘there is nothing for us in the Executive. We have to go into opposition,’" said Kane. “They have no mandate. Opposition became inevitable.”

The emergence of opposition politics does not mean that Northern Ireland’s wounds have completely healed. Society remains deeply divided along sectarian lines. Most people in Belfast live on streets that are 90 percent Catholic or Protestant.

There has been an upsurge in dissident republican violence on the centenary of the 1916 Easter Rising that led, eventually, to the partition of Ireland. Recently, U.K. security forces stepped up the threat level from moderate to substantial, which means an attack in Britain is “a strong possibility.”

But while the DUP and Sinn Fein still dominate, the political scene is becoming more fluid. The Green Party doubled its representation in Stormont to two earlier this month. The biggest surprise was the success of the anti-austerity People Before Profit, which also won two seats, remarkably topping the poll in the republican heartland of West Belfast.

For nationalists, in particular, the constitutional question — whether Northern Ireland should remain in the U.K. or unify with the Republic of Ireland — has become less salient, leading some to abandon Sinn Fein.

“Nationalists are apolitical now, they are comfortable in Northern Ireland. Also they don’t really trust Sinn Fein to govern. They see them as good at making the peace but are they any good at the next step in the process?” said Byrne.

Since 1998 Northern Ireland has lurched from crisis to crisis, often involving policing and security. Despite working side-by-side in government for the past eight years, the DUP still refuses to countenance former IRA members in control of justice. On Wednesday another political emergency was avoided when the Executive was formed with 29-year-old independent unionist Claire Sugden appointed to the role of justice minister.

While Northern Irish voters say they want a more normal politics, the old disputes around culture and identity remain unresolved, said Byrne.

“Listen to anyone and they will tell you the key issues are not legacy issues, or flags or the Troubles or culture, they are education, health, employment. The problem in Northern Ireland is it only takes one flashpoint to move back to the old politics.”

Peter Geoghegan is a writer and journalist based in Glasgow. His books include A Difficult Difference: Race, Religion and the New Northern Ireland (Irish Academic Press, 2010).