'It may be that the Government calculates the IRA will respond if taken at its own word'
A double conundrum lies at the heart of the present Blair-Ahern rescue operation aimed at putting the Irish peace process back on track and bringing some sense of stability to Northern Ireland's unsettled politics.
The first is why the question of policing has figured so prominently in this negotiation when David Trimble, the Unionist leader, declared at its start that IRA decommissioning was the only issue.
The second and greater riddle, and the one that might decide the fate of the process, is why Tony Blair is making such efforts to address republican points, especially on policing, in the apparent absence of an IRA guarantee to move on guns.
The first point is the easier to explain. For a year and a half, the IRA has formally had on the table an offer to start putting its weaponry beyond use. This prize is, however, surrounded by a thicket of qualifications and conditions.
Some of these are capable of multiple interpretations that would keep a courtroom of lawyers arguing for months: they have certainly kept republicans, Unionists and the Government arguing for more than a year.
But whatever the IRA meant by "the potential to remove the causes of conflict" and other hazy phrases, some bits seem clear enough. Decommissioning depends on far-reaching policing reform, and on demilitarisation: no development on these means no movement on guns.
Demilitarisation is a matter of degree rather than an absolute. It is a fair bet that Northern Ireland, given its history and the amount of hardware that is lying around, will never be completely demilitarised.
Policing is the crux. Huge changes are already under way as the Royal Ulster Constabulary is transformed into the Police Service of Northern Ireland, but republicans have a whole shopping list of additional demands.
The Unionist community tends to be against all of these, for a variety of reasons. First it is pretty much automatically against anything that has been put forward by republicans; and second the changing of the RUC's name has already inflicted a deep hurt on most protestants.
Half the protestants have been against the peace process since the start. Many more have swung against it because it has entailed changes in policing and other areas that they regard as defeats for them and victories for republicans and nationalists.
The undisputed benefits of the process have curiously little effect on this mindset. Last week the Government issued a hefty document detailing advances made during the process: it is doubtful whether it changed a single disillusioned protestant mind.
A large majority of protestants approve of having an assembly and executive in Belfast, giving some measure of local control. Yet, at a deeper level, Unionist angst and alienation is now so strong that most would rather have no local institutions at all rather than see the system continuing without IRA decommissioning.
David Trimble's action in resigning as First Minister at the beginning of this month reflected this reality. The keynote sentiment, as any protestant barber will tell you, is that "the republicans and nationalists get everything, we get nothing"
Which brings us to the second conundrum, for when the Blair-Ahern package is unveiled this week, it will contain more policing moves which will instantly be denounced as further appeasement of republicanism.
It has in fact already been so denounced, for last week Jeffrey Donaldson and David Burnside, two of the Unionistss' most energetic and, indeed, most ambitious MPs, dismissed the whole thing as a waste of time. This type of pre-emptive strike, known in Belfast as getting your retaliation in first, has guaranteed that the package will be attacked from many parts of the Unionist spectrum.
It is to be a balanced package, containing elements such as a review of marching legislation and the role of the Parades Commission, which has banned and re-routed many Orange marches. But even if the package is garlanded with a dozen such Unionist-friendly moves, it is difficult to imagine them balancing out the further policing concessions.
Everyone knows that what Unionists want is decommissioning. That is what Mr Trimble requires, and that is certainly what his divided Ulster Unionist Party will require before going back into devolved government.
In Unionist terms, therefore, the present negotiation will only be a balanced exercise if there are guns at the end of it. But any decommissioning will be a voluntary act since Mr Blair cannot force the IRA to move on the issue. They have to decide to do so themselves.
The great unanswered question is whether the Prime Minister is proceeding with the package on the basis of some private whisper from Gerry Adams, or whether he is simply travelling in hope and trusting in the logic of the IRA's stated position.
It has to be said that Mr Adams is not known for making secret pledges on behalf of the IRA. It may rather be that the Government has made the calculation that the IRA will respond if taken at its own word and if progress is made on policing.
It is certainly the case that the IRA may decide it is in its own interests to move. Without movement the Good Friday Agreement, which it strongly favours, is imperilled. The next two weeks may bring the agreement to the point of suspension, though it is possible that the Government can engineer an extension.
At one level the IRA can only but enjoy the spectacle of Unionism divided and warring against itself. But on another it regards the agreement as a valuable vehicle which has delivered great electoral rewards to Sinn Fein.
Unless Mr Blair already has an IRA assurance in his pocket, which seems unlikely, he must be banking on the analysis that the organisation will feel impelled to act to rescue the agreement. This week's package could therefore make or break the agreement: it had better be good.
A new edition of "Lost Lives" by David McKittrick et al, which details all the deaths of the Northern Ireland trouubles, has just been published by Mainstream Publishing of EdinburghReuse content