Northern Ireland's Troubles began with its police force front and center and in a very real sense may have ended with a grand compromise on the vexing question of where the ultimate control over policing should rest.

In many people's minds, Northern Ireland's Troubles began on Oct. 5, 1968, when civil rights demonstrators marching peacefully in Derry were beaten by baton-wielding police. Images of the attack were captured by television cameras and beamed into living rooms across Ireland and Britain.

Three months later, Catholic civil rights protesters marching from Belfast to Derry were accosted by a Protestant mob on Burntollet Bridge and beaten and stoned as members of the Royal Ulster Constabulary looked on and did little to intervene.

These incidents and many others convinced Catholic nationalists that policing was one of the major problems in the sectarian state that was Northern Ireland.

More than four decades later, much has changed there: Catholics and Protestants now share power in a fragile coalition government and the old RUC has been reformed and given a new name.

But the question of how policing would be controlled was at the heart of a standoff that threatened to bring down the North's power-sharing government and did take it to the edge of collapse.

For months, Sinn Fein, the leading Catholic political party in Northern Ireland, argued that control over policing and justice matters needed to be transferred from British officials in London to officials of the Assembly government in Belfast.

The Democratic Unionist Party, the largest Protestant party, said it would not support a transfer of power until it was convinced that the police and judiciary would be free of undue political interference, and the DUP also sought concessions on the emotional question of how Protestant marching-season parades are supervised.

Months of bargaining and brinksmanship came to a conclusion last month when British Prime Minster Gordon Brown and Irish Taoiseach Brian Cowen traveled to Hillsborough Castle outside Belfast to sign a compromise hammered out by the First Minister Peter Robinson of the DUP and Deputy First Minister Martin McGuinness of Sinn Fein.

Under the deal, Sinn Fein wins the devolution of police and justice powers that it sought and the DUP gains the protections it requested and the promise of a fresh look at the parades issue.

The transfer of police and judicial powers – the only governmental powers not yet shifted from London to Belfast – is now set to take place on April 12.

Officials said that the breakthrough could mark the true end to the Troubles. "This is the last chapter of a long and troubled story and the beginning of a new chapter after decades of violence, years of talks, weeks of stalemate," Brown said. Cowen called the deal "an essential step for peace, stability, and security in Northern Ireland"

McGuinness, who once battled the police as a former leader of the Irish Republican Army, celebrated the move. "This might just be the day when the political process in the North came of age," he said.

And the beleaguered Robinson, recovering from weeks of political and personal-life turmoil, heaved a sigh of relief and noted, "No future generation would forgive us for squandering the peace that has been so long fought for. I believe that we have taken a considerable step to secure the prize of a stable and peaceful Northern Ireland."

The breakthrough was celebrated by the U.S. government, with Secretary of State Hillary Clinton saying the accord "will help consolidate the hard-won gains of the past decade."

With the agreement now in place, British and Irish officials said that Clinton, whose interest in Northern Ireland dates back to her husband's presidency, will preside over a Northern Ireland investment conference to be held later this year.

While the devolution deal represents an important step forward on two public policy issues, it has the much larger significance of putting the North's power-sharing government on much firmer ground.

Speaking to reporters after the agreement was signed, Robinson said: "If I had said to any of you that we would be sitting here today having agreed to a way forward on policing and justice, and parading, and how to reinvigorate the executive, and that we would have unanimous support within our two parties, very few of you would have accepted such a claim. But that is precisely where we are."

McGuinness, whose relationship with Robinson has been strained and testy, in contrast to the surprisingly cordial relationship he enjoyed with Robinson's better-known predecessor, the Rev. Ian Paisley, predicted that better days lie ahead. "There is a better atmosphere now. Divided we are weak, united we are strong."

Strong and surprisingly united.