Only now, after months in the making, is its general shape emerging. It is regarded as seismic in that it represents a historic shift from the age-old republican principle that the weapons of war should never be surrendered or otherwise rendered unusable.
After all the years of the IRA and Sinn Fein expressing implacable opposition to decommissioning, the republicans were suddenly putting their guns on the table, as it were, and indicating that they were prepared to take them out of commission in exchange for a place in government.
Since the inner workings of the republican movement remain very much of a mystery, even to the intelligence services who are given the task of penetrating it, the exact conception of the plan is unknown. But its origins go back at least until early May, when Sinn Fein's chief negotiator, Martin McGuinness, flew to Washington to brief senior officials in the Clinton administration.
At the heart of the proposal is an offer of decommissioning which amounts to not just a token gesture but the prospect of total decommissioning. It is this which has so excited both the British and Irish governments, who view it not simply as the key to unlocking the present impasse but as potentially opening a new and more peaceful era of Irish history.
Sinn Fein wants the immediate formation of a new Northern Ireland administration as provided for in last year's Good Friday Agreement. In exchange, it is offering proposals aimed, it says, at taking the gun out of Irish politics for good.
The proposal says that an interlocutor would be appointed between the IRA and the international decommissioning committee within a week. It makes mention of a start to decommissioning by December of this year, with completion envisaged by May 2000, the second anniversary of the Good Friday Agreement. It envisages decommissioning happening in various phases, with built-in checking mechanisms to verify that it is a "credible and certifiable" process.
If republicans were seen to go back on their word, the proposition agrees that the new executive should be wound up. These are held to constitute fail-safe mechanisms to ensure that the business of decommissioning proceeds as promised. All of the above was to take the form of solemn assurances from Sinn Fein, rather than the IRA.
This proposal, while not meeting the exact demands of David Trimble's Ulster Unionist Party, was regarded by Mr Blair and his Irish counterpart, Bertie Ahern, as the key to a breakthrough. When conveyed to Mr Trimble's Ulster Unionists, however, it seemed to plunge the Unionists in- to something close to disarray.
On the one hand, the proposition seemed to hold out the extraordinary prospect of republican disarmament within a year. But on the other, it was not in line with the party's precise policy, which was to demand decommissioning simultaneously with the formation of a new executive.
The Ulster Unionists tend to be a literally minded party, which means that they favour having their demands addressed to the letter. The party is also riven with divisions over policy and personality, which means that Mr Trimble has had difficulty in holding it together in these eventful times.
He has lately, for example, included Jeffrey Donaldson in his negotiating team: a most unusual move, given that the MP is a declared opponent of the Good Friday Agreement. The adoption of the simultaneous decommissioning policy was, therefore, not just a demand but an important device aimed at holding an unsteady party together.
Against this background, some in Mr Trimble's assembly party saw the Sinn Fein proposal not as a historic opportunity but as an awkward and even unwelcome gambit. This attitude was overlaid by the traditional Unionist suspicion of republicanism, which led to fears that it might all be a deceitful stratagem rather than a genuine overture.
The result was much confusion in the Unionist ranks as the party scrambled to formulate a response. Mr Trimble argued for certainty and sanctions, demanding to hear not just from Sinn Fein but also from the IRA directly that decommissioning was at hand.
He wanted the decommissioning schedule to begin not in six months but in two weeks' time; meanwhile, he wanted the setting up of the new executive to be delayed. If decommissioning stopped, he wanted to keep the executive in being, but to have Sinn Fein expelled from it.
One of his problems was that the republican proposition, although potentially historic, did not meet his party's precise demands. Acceptance of it might, therefore, produce a split. On the other hand, London, Dublin and Washington were pressing him to take it as the best offer he would ever get.
So he was a leader with the unprecedented and priceless prospect of complete IRA disarmament possibly within his grasp: a leader faced with the agonising choice of sundering his party or throwing away Ireland's best-ever chance for peace. These huge and conflicting pressures help explain why this turned into such a long, difficult and fraught negotiation.Reuse content