Tony Blair and Bertie Ahern, his Irish counterpart, will seek today to launch what has been described as a Plan B for the Northern Ireland peace process. With the murder of Denis Donaldson, the Sinn Fein organiser turned police informant, the B might well, alas, stand for “been sabotaged”. Although Sinn Fein and the IRA have issued (not implausible) denials about any involvement in this killing, all but the most paranoid suspect that Mr Donaldson was shot either by a dissident faction within the IRA or a renegade element of the “republican family”. If this deed was designed to destabilise political bargaining, then, in truth, it has succeeded.

Not that it would have taken much, sadly, to achieve that end. The scheme that Mr Blair and Mr Ahern intend to promote has an air of desperation to it. It involves restoring the Northern Ireland Assembly, which has been dormant since 2003 (with the exception of its subsidised canteen and the salaries department), but on a “shadow basis”. The political parties are to be encouraged to meet together for six weeks before a summer recess and then again in the autumn until November 24, by which time either a fully devolved settlement is to be have been hammered out — “or else”.

It would be churlish not to wish this plan well but optimistic to believe that it will prosper. While the parties might turn up for the first day of the shadow Assembly (although this must now be in doubt), they totally disagree about what to do next. Sinn Fein is not interested in backing a body that does not turn swiftly into a real power-sharing executive, while the DUP can live with a semi-permanent interim Assembly if it puts off the moment when its representatives have to sit in any Cabinet with the likes of Martin McGuinness. The chances of a serious debate on, for example, universal support for the police service in the Province is meagre.

This is in large part because current electoral incentives provide the Democratic Unionist Party, especially, with every reason to prevaricate for longer. The next elections to the Assembly are not scheduled until May next year and the vote-maximising strategy for the Rev Ian Paisley and company is to be tough until that point, marginalise the Ulster Unionist Party to a rump at this poll and then (perhaps) reach a calculation about whether it is worth contemplating a deal with Sinn Fein that would permit devolution to resume.

If Plan B does come to nothing, Mr Blair and Mr Ahern must be ready to take a risk on Plan C — namely, to consult the voters. The date of the Assembly election should be brought forward to this autumn. By that time, there will have been several more reports by the International Monitoring Commission — the organisation that has the task of assessing paramilitary activities of all kinds — and the people of the Province will be in a position to judge whether the IRA has lived up to its pledge to operate by solely peaceful methods. On the basis of actual votes and a fresh mandate, ministers could call the Assembly back into work and ask it to reach an accord on an executive, or be disbanded if it cannot do so.

There is a sizeable chance that, even then, no understanding would emerge. Supporters of the peace process would have to search for a Plan D (which, in reality, stands for “don’t know”). It would be better, however, to do this on the basis of the ballot box than any “shadow” arrangement. Ulster is at relative peace, yet in political limbo. It is a dangerous no man’s land to occupy.