The Northern Ireland peace process will be thrown into one of its biggest crises yet when the Ulster Unionist Party leader, David Trimble, announces today that his party's ministers will pull out of the fledgling Belfast administration.
Mr Trimble is likely to give some days' formal notice of the withdrawal, having promised to provide "a soft landing" for the ending of devolution.
But it seems inevitable that the cross-community administration will go into storage before the end of the month. If this happens, most observers are pessimistic about the chances of reviving the government.
There is widespread agreement that only a significant act of arms decommissioning by the IRA can avert the looming crisis. Many believe this is at least possible but there are no guarantees that such a move is on the cards.
It is reliably reported that intense debate has been going on within the senior ranks of the IRA on whether and how to move on decommissioning. Many believe that the "politicos" are in the ascendancy over the militarists.
Government and security sources yesterday discounted a weekend newspaper report that Martin McGuinness, the Sinn Fein MP, had recently become IRA chief of staff. But he is regarded as a key figure in the republican movement, and observers have noted that he said in a recent BBC interview that he was in favour of putting arms beyond use.
It is still unclear how the IRA will react to the events of 11 September in the United States, and whether this will propel it in the direction of putting arms beyond use. Both the IRA and Sinn Fein have recently appeared eager to avoid being seen as part of the international terrorist menace.
Any move aimed at saving the Belfast administration from closure would have to come within days and would have to be of sufficient magnitude to impress the many doubters within the Unionist party.
In the Assembly today, Mr Trimble is to propose the expulsion of Sinn Fein from government because of the lack of IRA decommissioning. His motion is expected to fail since to succeed it would need to have the support of nationalist Assembly members, and this will not be forthcoming.
He has said that, in the event of its failure, his party's three ministers would withdraw from office. Assuming this takes place over a period of some days, it will leave John Reid, the Secretary of State for Northern Ireland, with a week to consider how to react.
Forming a new Unionist-free executive is not a practical proposition and the idea of fresh Assembly elections is not in favour. This leaves little option but to suspend the Assembly and initiate a review.
An unusually optimistic note was struck yesterday by George Mitchell, who once chaired talks on Northern Ireland. He said he was confident the process would survive the current deadlock. The former US senator said he remained optimistic because people did not want to return to conflict.
He added: "Admittedly there are many problems. They are very severe. Implementation of the Good Friday Agreement has not gone as well as could have been hoped for, but in the end I think people don't want to go back to conflict."
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