Ten years ago, 8 per cent of Northern Ireland's police were Catholics. Today the figure is 27.8 per cent, such is the sea change in the mindset of the nationalist population since the 1998 Good Friday Agreement.
Northern Ireland's nationalists have withheld consent from the state and its police force, which they perceived as the paramilitary wing of the Ulster Unionist Party, since its creation in 1921. "Ninety per cent Protestant and one hundred per cent Unionist" was the slogan. Now, as a result of Friday's agreement at Hillsborough Castle, the political representatives of nationalists will sit alongside Unionists in an executive responsible for policing and justice.
Gordon Brown said Friday's deal "closed the last chapter of a long and troubled history". He spoke of a "momentous journey", as the Sinn Fein deputy First Minister, Martin McGuinness, stood side by side with the prime minister. McGuinness, a former IRA leader, has moved from planning how to kill policemen to running an administration that, if all goes to plan, will oversee policing policy.
It is the former status of McGuinness and of other Sinn Fein colleagues in the Stormont assembly which has made the decision to devolve power over policing and justice so difficult for Unionists to accept and has made them delay so long. Even sharing power with Sinn Fein in 2007 caused a split in the Democratic Unionist Party, the dominant grouping in unionism. To allow Sinn Fein to get anywhere near policing and justice has, until Friday, remained a step too far.
The Unionists could not understand why devolving these powers was so important to Sinn Fein. In 2007, the party had made the seismic move to recognise the new police service, the PSNI. That move was conditional on a Department of Justice for Northern Ireland being established. For Sinn Fein it was essential that it be seen to run all aspects of the state it had given its consent to for the first time. Policing and justice are such crucial aspects because Sinn Fein needed to fireproof itself against republican critics and armed dissidents who accuse it of administering British justice. After the Hillsborough Castle agreement, that accusation has no force.
To the Democratic Unionist Party all that ideology is irrelevant. The DUP's priority was to fireproof itself against its own hard-liners, so it introduced Orange marches as a counterweight in the negotiations. Friday's outcome has balanced movement towards devolution of policing and justice scheduled for 12 April against new arrangements for authorising controversial Orange marches, a framework for which must be pencilled in by March. In short, negotiations still continue.
Whether the pieces fall into place in March and April depends on a new spirit emerging between Sinn Fein and the DUP. The preamble to the agreement makes much of partnership, mutual respect and equality, qualities absent in the DUP's attitude to individual Sinn Fein assembly members. There is suspicion that former IRA members have not changed enough to be trusted. To assuage such concerns, DUP leader Peter Robinson talked of a "clever device", so far known only to him, to guarantee Sinn Fein fulfils its obligations.
Some senior DUP figures remain dissatisfied, especially those MPs who will be facing the Unionist electorate in May. However, the alternative was a snap assembly election which could see Sinn Fein emerge as the largest party, with unionism divided three ways.
Managing his backwoodsmen over the next three months will be a test of Peter Robinson's leadership. If he succeeds he will achieve something no Unionist leader has managed, namely, to persuade Unionists to live on equal terms with republicans.
Brian Feeney is an author and historian