The Unionist community has been conned about decommissioning since the peace process started in 1994. That duplicity, allied to a failure to explain how the agreement represents the best deal for Northern Ireland, may scuttle the deal, if not on May 22nd, then once the new assembly gets going.
Following the first IRA ceasefire in August 1994, unionists were told by the British government that there would be no all-party talks involving Sinn Fein until there had been a start to the decommissioning of IRA arms. The then Taoiseach, John Bruton, briefly endorsed this view. Dick Spring had done so previously.
All-party talks eventually started on the understanding, as stated by the British and Irish governments, that during the talks decommissioning would begin.
The Rev Ian Paisley told the House of Commons on April 22nd last: "I was at the talks on the condition that they would not proceed until the arsenal of murder weapons was surrendered. That commitment was given to me in Downing Street again and again by the prime minister of the day [John Major]."
Instead, a new ruse was devised. The talks were to proceed on a "twin track", one which supposedly provided for decommissioning to be agreed and implemented along one track, while the substantive talks proceeded upon the other. The mechanism was bogus. Nothing happened on the decommissioning track.
The agreement decouples decommissioning from every other aspect of it. It is manifest that, for instance, Sinn Fein representatives can take their place in the new assembly and on the new executive without decommissioning taking place.
Nevertheless, Tony Blair, in the week following the signing of the agreement, sought to give precisely the opposite impression. He backed off that line following a meeting with Sinn Fein in Downing Street, and the mild expression of disappointment by the British and Irish governments over the IRA announcement that there would be no decommissioning is testimony to their acceptance of the reality.
Is it any wonder that unionists are aghast that on the issue which was singled out to be the basis for their reassurance - that former terrorists would be engaged in the political process only after the hugely symbolic gesture of arms surrender - should be the issue upon which there has been the most spectacular duplicity?
It was clear there would be no decommissioning of IRA arms, not before the talks, not during the talks, not at the end of the talks, not ever. For those who did not know this otherwise, George Mitchell was told that by Sinn Fein and probably more explicitly by people speaking for the IRA in 1995, and said so in his report.
This was the reality because the basis upon which the IRA was prepared to engage in the peace process was an acknowledgment that it had been undefeated in the "war". The surrender of weapons would be a symbol of surrender. That could not, and will not, happen.
It was, therefore, disingenuous for the British, aided and abetted for a while by the Irish, to pretend that decommissioning was an integral part of the peace process involving Sinn Fein. It was also stupid. The unionists should have been told the truth from the outset and about the inevitable shape of any likely agreement.
The truth being that there would be no decommissioning and that any likely agreement would have to involve the release of prisoners, the reform of the RUC, an all-Ireland institutional dimension, and an executive reflective of all parties that achieved an electoral mandate.
The problem has been that nobody, not the British or Irish government and, especially, the Ulster Unionist Party, sought to win support among unionists for the kind of agreement that was necessary.
Nobody was campaigning among the unionist electorate for recognition that, because the Northern Ireland state had failed previously to win the broad consensus necessary to political stability and justice, there would have to be radical change.
That there would have to be an all-Ireland dimension to a settlement that alone could give the recognition to the nationalist community that the old Northern Ireland state had withheld.
That given the Sinn Fein electoral mandate, and the palpable support which the IRA enjoyed, any settlement should ideally involve them, should rope them in rather than seek to perpetuate their exclusion. And that this necessarily involved the release of prisoners and RUC reform.
There is nobody even now acknowledging that there is a price to be paid by unionists - but it is a price worth paying. And the reason it is worth paying is that, for the first time, Northern Ireland may enjoy stability founded on consensus.
Robert McCartney has challenged the stability argument. It, not decommissioning or the release of prisoners or anything else, is the central issue at stake for unionists and everyone else. He has argued that because the nationalist community, notably Sinn Fein, regards the agreement as "transitional", it will be fundamentally unstable.
He told the House of Commons, also on April 22nd: "The [new] assembly will be a constant unstable battle of political attrition that will render the prospects of peace and reconciliation highly unlikely."
He went on: "I am opposed to a process and an agreement that I really believe will create in Northern Ireland a state in transit. States in transit all over the world, from Yugoslavia to Lebanon, provide a field day for warring paramilitary groups, who exploit and inflame the communities they claim to represent."
The argument ignores two elements. Firstly, that while Northern Ireland seemed to represent a state set in stone it was deeply unstable because of the absence of widespread consensus. The new state, because of widespread consensus (that is, if it attains widespread unionist as well as nationalist consensus) will be stable.
And, secondly, as for transition, why should that be a factor for instability when, for the first time, there is a consensus about the process of transition around the principle of consent?
Mr McCartney and others argue that Sinn Fein continues to resile from the consent principle. Surely the evidence is to the contrary. By endorsing the agreement, it endorses one of its key elements. And what is wrong if it should seek to change the agreement within terms provided by the agreement?
It may still not be too late to convince a majority of unionists that, in spite of the decommissioning factor, in spite of the prisoner releases, in spite of the all-Ireland dimension, the reform of the RUC and the prospect of Gerry Adams and Martin McGuinness being in government, it represents a good deal for them.
That it can secure for them a state founded on consensus and on mutual respect. And, incidentally, it can end violence.