Muwaffaq al-Rubaie, the Iraqi government’s national-security adviser, says he took one big idea home with him following a trip to Belfast last week. When you enter negotiations, you should have no preconditions; they only get in the way of settlement.

This is high on the standard “list of lessons from Northern Ireland” that British-government advisers and academic conflict-resolution experts pass on to visitors from trouble zones such as Iraq, the Balkans and Sri Lanka.

There is also a stricture, muttered sotto voce by the Brits, to keep lines of communication open with your opponents, no matter how difficult or violent the situation. Sun Tsu’s maxim — if your enemy looks like retreating, be prepared to build him a golden bridge — is sometimes added as a final flourish.

All sound advice, and it’s no wonder the Iraqis were so taken with it. The only pity is that the two parties now at the centre of the political process in Northern Ireland are doing the opposite. Friday was the deadline for local party assent to the St Andrews agreement. Instead, the DUP and Sinn Fein came up with a list of preconditions.

Take the DUP leader, Ian Paisley. “The party will continue with the work in progress to ensure up-front delivery by government and republicans,” he stated. “As Sinn Fein is not yet ready to take the decisive step forward on policing, the DUP is not required to commit to any aspect of power-sharing in advance of such certainty.”

Sinn Fein also loaded on the preconditions. St Andrews, the party said, “could represent a way forward”, but only “subject to delivery” on issues such as the devolution of policing and justice.

In the strictest terms this amounts to a rejection of the St Andrews agreement, which looked forward to a process of reciprocal confidence-building by the two parties, a sort of virtuous spiral of gestures by which each would build golden bridges of trust to assist the other’s retreat.

On October 17 Paisley was to have attended the first of a series of regular meetings of a new Programme for Government Committee, along with the leadership of Sinn Fein and other parties. Fat chance. He refused to go until his preconditions were met.

Sinn Fein’s ruling ard comhairle was supposed to call an ard fheis at which the party leadership would recommend support for the PSNI, subject to devolution of policing powers. They never did. They said they would await delivery.

All this was to pave the way for an acceptance in principle of the St Andrews agreement last Friday. As part of the process Paisley was supposed to have indicated that, subject to progress on policing in the coming weeks, he would be prepared to enter government with Sinn Fein.

If that had been achieved, we could have looked forward to seeing Paisley and Sinn Fein’s Martin McGuinness nominated as first and deputy-first ministers on November 24 and taking office next March.

In the interim, Sinn Fein would have held its ard fheis and empowered future Sinn Fein ministers to endorse the PSNI.

The International Monitoring Commission would also have reported, presumably to reassure the DUP that the IRA and Sinn Fein were keeping to their commitments on peace.

Times Recommends

• Michael Jackson: Not the final chapter
• Indian Army spends10m rupees on golf buggies
• Brüno toned down for 15 rating