If this was an IRA operation with the approval of the IRA leadership, the peace process is in very serious trouble. In Government circles last night, that if was being emphasised. While some security sources said they believe this was a sanctioned IRA importation, others believed it may have been an unsanctioned or freelance operation. Government sources were yesterday echoing the official Garda line that the investigation is still continuing and that they retain an open mind.

A Government spokesman declined to comment on the political implications of the attempted arms importation until the facts are known.

The mute political reaction to the discovery of the gun running operation is a reflection of the time of year. Almost all politicians involved in the North's political process have gone on holidays, to return in September to participate in Senator George Mitchell's search for a resolution of the deadlock over the formation of the power sharing executive and decommissioning.

Into this month-long political vacuum comes a mysterious attempted importation of weapons as well as an unexplained execution

of a man in west Belfast. The worst case scenario is that the IRA is importing weapons with a view to resuming its campaign of violence, possibly with new guns which could not be traced to past IRA shootings.

The murder in west Belfast on Thursday night adds to the fear that Republican violence has not gone away. The Sinn Fein leader Gerry Adams has said he is "shocked and concerned" at the killing, and it is unclear who was responsible.

While political reaction has been quiet, this may not last. If the arms importation is shown to have been sanctioned by the IRA, then the political process will face a serious crisis in September. When killings were linked to the IRA during the talks leading to the Belfast Agreement, Sinn Fein was excluded from that talks process for a period. The pledge of office for members of the Northern Ireland Executive includes a "commitment to non-violence and exclusively peaceful and democratic means".

There is some speculation that the weapons, even if they were being imported by the IRA, were intended for so-called punishment shootings rather than other paramilitary attacks. They were mainly handguns and ammunition, the type of weapon that would be used in "up close" assassinations.

However this would not mitigate the clamour for Sinn Fein exclusion from the political process. According to the Mitchell Principles to carry out punishment attacks is to breach the ceasefire.

So whatever the purpose of the weapons, if this was an IRA operation, moves to exclude Sinn Fein from an executive, if it is formed, can be expected. If the IRA were deemed to be no longer holding to "a complete and unequivocal ceasefire" then IRA prisoner releases would be halted If the arms importation was not sanctioned by the IRA, there are a number of alternative explanations, some of which would also have political consequences.

It is possible that the operation was planned and carried out by IRA members without the sanction of the leadership. While this would mean there would be less political pressure to exclude Sinn Fein from the political process, it would also suggest a serious division within the IRA.

This would be severely damaging to the long-term strategy of the Irish and British Governments which underpins the peace process. For the two governments, the real importance of Sinn Fein involvement in the political process is the extent to which they can lead the republican movement and its supporters away from violence.

Internal IRA division, with a significant section of the organisation re-arming, would confirm fears that part of the organisation is refusing to be led by the Sinn Fein leadership and is preparing for a return to war.

The third possibility is that the arms importation was being carried out by maverick Republican elements who have either severed any association they had with the IRA, or never had such an association.

This would be the least politically damaging of the possibilities, but it would still increase concern about the intentions and the capability of non-IRA republican paramilitaries.