THE undercover operation which resulted in Thursday's find at Clonaslee, in the Slieve Bloom mountain area, uncovered what gardai believe was the IRA's primary bomb and mortar-manufacturing facility.
Further attacks such as that on Manchester would almost certainly have prompted the loyalist paramilitary "backlash" against targets in the Republic, which could have completely destabilised what remains of the peace process.
Senior security sources were speculating yesterday that the Garda operation has undermined the IRA war plans and provided another opportunity to those opposed to "armed struggle" to reassert their position within the broad "republican movement", which comprises Sinn Fein and the IRA.
Gardai believe there is a "silent" majority within the republican movement that is not happy with the IRA leadership's position on the primacy of "armed struggle", but that this group is more or less subjugated by the IRA's military strength and readiness to use violence.
It is possible that the murder of Det Garda Jerry McCabe precipitated the set of circumstances which is turning the tables on the IRA militarists.
Gardai took Det Garda McCabe's death "very, very personally", as one officer put it, and, while the Government remained reticent about publicly pointing the finger at the IRA, the Garda was very clear about the threat posed by the militant republicans in this State.
It was known within an hour that the Munster IRA was responsible for killing Det Garda McCabe and injuring his colleague, Det Garda Ben O'Sullivan, a fact conveyed to the Government on the morning of the murder.
Almost immediately Garda management set in train one of the most intense anti-IRA operations in a decade, reversing the de facto policy since the IRA ceasefire whereby anti-IRA operations were stopped.
Gardai were also greatly helped, it is now clear, by a flow of information and intelligence such as has not been encountered in many years. The murder of Det Garda McCabe, it appears, combined with the IRA's flouting of the peace process, had created a widespread sense of antipathy towards the IRA. Some of the in- formation must be coming from republicans who no longer support the leadership's position on "armed struggle".
Gardai were able to avail of this goodwill and flow of information in the past-week and were, eventually, led to the bomb factory at Clonaslee.
The extent of the IRA's capability to further wage war will be tested by how it reacts to the discovery of the bomb factory.
Gardai were aware that the IRA structure in the Republic is central to its ability to wage war in what it terms the "war zone", an area basically comprising Britain and Northern Ireland.
Since Det Garda McCabe's murder the Garda has been striking at the heart of the IRA's operations in the Republic.
The Clonaslee bomb factory is in the heart of the midlands area where, it has been believed for years, the IRA has been assembling military equipment for use in Britain and Northern Ireland.
The massive search operation in Munster, where the IRA maintains its major arms dumps, has undoubtedly interrupted the supply source of weapons.
Further Garda operations along the Border, including increased surveillance of IRA groups from Louth to Donegal, has also reportedly led to a reduction in movements by known republicans. Gardai are confident that their successes over the past three weeks will result in a severe diminution of the IRA's capacities for some time.
Information gleaned from the factory by Garda and Army ordinance and ballistics experts will also be of great assistance to their counterparts in the RUC and British army who might in the future have to deal with unexploded bombs of the type manufactured in Clonaslee.
All this, some gardai believe, will combine to place unprecedented pressure on the IRA leadership.
It is also hoped that the shift of support away from the IRA hardliners, which is manifesting itself in the flow of information to the Garda, will cause a crisis of confidence in the leadership. The IRA has always depended on widespread support among its sympathisers. Without this, it will be able to mount only limited military activity and always be concerned about its own security.