The short but significant document, hatched in a series of telephone calls between Tony Blair in Tokyo and Bertie Ahern in Dublin, puts forward the new ideas not as a blueprint for a settlement but as their recommendations for the shape of future negotiations in the Stormont multi-party talks.
Formidable problems remain in finding agreement on how the various elements can be slotted into place together. Unionists, for example, will be intent on forging the strongest possible east-west connections in an attempt to strengthen Northern Ireland's links with Britain.
Since nationalists regard north-south links within Ireland as their priority, they will by contrast push for maximum powers to be conferred on a new north-south institution. Reconciling these two approaches will form the stuff of negotiation in the months ahead.
No one believes that achieving a successful conclusion will be easy, but the document produced yesterday has the approval of both London and Dublin, while both the Ulster Unionists and SDLP signalled their sense that they can live with it. One crucial, and as yet unanswered, question is whether Sinn Fein and the republican community generally will be prepared to leave their aspiration for Irish unity to one side for the moment, and help build a more complex compromise arrangement.
If all the elements sketched out in the document do provide the shape of an eventual agreement then new arrangements will look something like this:
A new Belfast assembly with considerable devolved powers, together with safeguards to ensure that both Unionists and nationalists have a share of power.
An intergovernmental council will bring together representatives of London, Dublin, Belfast, Scotland and Wales.
A north-south ministerial council will link the two parts of Ireland. It will be a decision-making body served by new bodies and mechanisms.
A Bill of Rights and other measures to protect civil and political rights and promote equality.
Measures to deal with the questions of prisoners, security, policing and arms decommissioning.
For Unionists such an outline holds out the prospect of ending the 1985 Anglo-Irish agreement, which they detest, and of making important changes to the Irish constitution, to which they also object. They have also been against the idea of a powerful north-south institution, but will draw comfort from the fact that Scotland and Wales will be incorporated into the new arrangements. Their inclusion should help provide reassurance that the union with Britain is not being sundered.
Nationalists will welcome the north-south institution and the decidedly Anglo-Irish character of an arrangement which would see Dublin heavily involved in most aspects of the new structures. Their concern about alterations to the Irish constitution will be alleviated by the proposition that this would be balanced by changes to the Government of Ireland Act which established the state of Northern Ireland in 1920.
In one sense, these ideas provide a plausible outline of how - with give and take and hopefully a sense of goodwill - a historic new arrangement might work. But the devil is in the detail and there literally thousands of difficult details to be worked out.
It is also clear that as the May deadline for the talks approaches, the various splinter groups - both loyalist and republican - can be expected to try to step up violence in an effort to derail the whole process. Furthermore, there are suspicions that the Ulster Defence Association, whose political representatives are in the talks, may believe it can continue to carry out killings without incurring the political penalty of expulsion from Stormont.
The two governments hope their ideas, which are entitled "propositions on heads of agreement" will mark a turning-point in a talks process which has so far produced a quagmire of procedural wrangling and a surfeit of generalities. London and Dublin now want to concentrate minds and get down to specifics.Reuse content