Creating a fear that all is being seen and heard
The intelligence war against the dissident factions is not just about getting inside those organisations and inside their operations – but getting inside their heads.
And, in this hidden world of spookery, it is not just about what MI5 and PSNI Intelligence know, but what those different IRA groups think they know.
This is the importance of the 'hard stop' operations when dissidents transporting arms and explosives are stopped in their tracks – and the importance of arresting leadership figures.
The more groups such as the dissident IRA coalition Oglaigh na hEireann and the Continuity IRA, are interrupted and disrupted, then the more they have to think about their next conversation and their next move.
Part of the intelligence war is about making them think that they can't talk in their sleep, planting that seed and fear that everything is compromised and that everything is seen and heard.
We've seen throughout the years of conflict here how covert surveillance is done. Listening devices and cameras have been built into cars, placed inside homes and offices and concealed in all sorts of places.
These things were in play long before the dissidents took the stage.
But it is not just about the technical side of intelligence. Human sources of listening and watching are all part of the play. These are the agents inside the organisations, who talk from the inside to their handlers in the Security Service.
And it makes those planning the next attacks think not just about how they communicate, but who they're talking to and who they might really be talking to.
We know in the past that agents have been inside bomb teams. That explosives have been removed from devices and replaced with another substance as part of what is called "substitution". Every time a bomb only partially detonates or is discovered, the dissidents will be wondering.
The watching and listening happens all the time. And they know it.