Sir Patrick said that republicans would firstly have to demonstrate a willingness in principle to disarm, and secondly come to an understanding on the practicalities of decommissioning. Then, in "Washington 3," he insisted on "the actual decommissioning of some arms" in advance of round- table talks.
In the opinion of many observers that one small phrase has the capacity to derail the entire Irish process, for the Anglo-Irish disagreement over it is a symptom of a vast gulf in perception that exists between Britain and Ireland.
To conservative middle England it may seem common sense to assume that, if the IRA is genuine in indicating that it has abandoned terrorism, the organisation should now methodically set about the task of divesting itself of its sizeable armoury.
To much of nationalist Ireland, however, insistence on an arms handover is a more dangerous step than allowing the guns to stay out there. This is because of the fear that any present attempt to decommission would lead to a split in the republican movement and hence a resumption of violence.
After the Washington speech Dublin signalled its belief that it did not believe this should be a pre-condition for talks, since in its opinion Gerry Adams could not deliver any arms. Sir Patrick Mayhew, by contrast, believes that Mr Adams could deliver but has simply chosen not to.
Dublin's nightmare scenario was that in the summit it would be drawn into endorsing a British position which it regards as profoundly mistaken. It believes that sticking to Washington 3, far from delivering arms, is a recipe for protracted stalemate; and that in a permanent stand-off the ceasefire, and the peace process, would gradually unravel.
In the run-up to the summit the British would not move from Washington 3 and the Irish would not move towards it. In these circumstances the Irish saw no point in proceeding with the proposed disarming commission, since it viewed the commission as essentially a device to get everyone off their hooks.
Behind all this lies a critical political judgment on what is going on within the republican movement, its commitment to the peace process, and what lies in the realms of the possible for its leadership.
The British view is that the strength of the Adams leadership is robust enough to endure a fair amount of pressure; that it must be confronted with Washington 3 until it moves; and that this is the way to advance the process.
The Dublin view is that Mr Adams has stuck his neck out far enough in bringing about the ceasefire; that if he stuck if out further it might be chopped off; and that pushing Washington 3 could test the whole process to the point of destruction.
To British observers it may seem unacceptable to think of Sinn Fein making its way to the conference table without a single IRA bullet being produced, but to nationalist Ireland things look different, since there is a long tradition of allowing the guns to fall into disuse rather than insisting they be surrendered.
The British may be affronted by the idea of people sitting at the negotiating table while their friends remain armed; the Irish tend to point out that that's how it's always been done, and indeed that that's how it's still being done in places like Bosnia and the Middle East.
Republicans can also point out that they are not the only armed element in Northern Ireland: there are many loyalists with guns, and indeed more than one Unionist politician has a shady past. In the Irish Republic the fact that more than one of its mainstream parties was founded by one-time gunmen provides historical sanction for simply leaving the guns to rust.
The question of the state of opinion within the notoriously secretive republican movement is a difficult one.
It has to be said, however, that Dublin has a better record than London in divining what is going on in those murky waters.
The previous Dublin government took huge political risks, far greater than any taken by John Major, in pursuing the peace process while IRA and loyalist killings continued. This was based on a sense that the republican leadership was genuine.
The entire British intelligence apparatus, on the other hand, failed to predict the IRA's complete cessation of violence: security chiefs readily admit they were expecting perhaps a three-month ceasefire.
This same intelligence apparatus is assuring Government ministers that Mr Adams has room for manoeuvre, and that the way ahead is to keep pushing for Washington 3.Reuse content