Let us assume that the Police Federation might be wrong in its assessment that there are 650 active dissident republicans determined to bring down the power-sharing settlement.
For caution's sake, let us calculate that the figure is closer to half that number. This means that there could be up to 325 hardline republicans opposed to the ceasefire and dedicated to continuing the 'armed struggle'.
Yet, even on its own, that downgraded figure should cause alarm among security mandarins on either side of the border and the Irish Sea.
Since their evolution from mass movements into cell-like structures in the early-1970s, paramilitary organisations have got smaller. Some, such as the UDA, existed for a time in parallel. They would put thousands of men in combat jackets onto the streets, but, at the same time, run tighter, relatively miniscule units, whose sole purpose was murder.
The numbers in the murder-squads of, say, the UFF, were tiny compared to the massed ranks of the UDA marching around central Belfast between 1972 and 1974.
Yet a small band of ruthless killers could terrorise the entire Catholic population.
This 'cell' structure re-emerged in the lower Shankill during the late-1980s with Johnny Adair's so-called 'C' company. Adair had only a few trusted lieutenants whom he used to re-ignite sectarian warfare in greater Belfast.
Although it is impossible to be scientific about it, the actual number of killers 'Mad Dog' sent out to attack the nationalist community probably didn't exceed 20.
Indeed, in one case - that of notorious killer Stephen 'Top Gun' McKeague - one man was responsible for a very high proportion of the UFF murders in north and west Belfast.
The Provisionals, however, were the masters of refining and re-defining terrorism.
While they, too, were fond of putting on mass shows of strength, by the late-1970s, the IRA 'cutting-edge' was a pared-down, but utterly effective, killing-machine.
Fearing infiltration by informers, key active service units (ASUs) even cloaked their identifies from fellow IRA units.
One story has gone around republican circles regarding the 1996 Canary Wharf bomb which broke the IRA's ceasefire 17 months earlier.
Although the massive device which devastated that part of London's docklands was constructed in south Armagh, the bomb was transported to London and set off by an IRA unit from east Tyrone who were trusted by the organisation's then chief of staff. It is said he was so distrustful of anyone outside his own control that the men who picked up the bomb wore masks so their 'comrades' would not be able to identify them.
Small, therefore, to borrow and pervert the economist E F Schumacher's famous argument, was in terrorist minds beautiful - and essential in their 'war' with the British state.
It is also worth pointing out that the term 'dissident republican' was first used not to describe the modern Real or Continuity IRAs.
In fact, it was coined in the mid-1970s when the Official IRA was engaged in a shooting war with the fledgling INLA.
The INLA later evolved into a small, but murderous group which exploded bombs in the House of Commons car-park, killing Airey Neave - one of Margaret Thatcher's closest aides. It also committed one of the worst atrocities of the Troubles - the 1982 Droppin' Well massacre.
But for all its penchant for internal schisms - always settled at the end of a gun barrel - the INLA was capable of inflicting murder and mayhem on the streets, despite its small size.
Again, it is hard to be exact, but according to one INLA veteran, at the height of its violent campaign in the early-1980s, there may not have been more than 300 armed activists engaged at the coalface of its 'armed struggle'; small enough for the security forces ultimately to curtail their violence, but still large enough to inflict death and destruction. Of course, the security forces are at a greater advantage today vis-a-vis terror groups than they were in the 1970s and 1980s.
Not only have they learned so much on the way, but developments in surveillance technology have allowed them to spy and pry into the movements of terror suspects like never before.
Moreover, money remains the most potent weapon of all in their arsenal.
The state's war chest enables it to recruit informers, bribe the corrupt and the debt-ridden, buy off even, seemingly, the most militant of activists.
State forces, it is now emerging, were successful in doing this even within the Provisionals, as the Denis Donaldson and Stakeknife scandals have shown. But there remains the problem of true believers - even if their numbers are small and their overall support in the community negligible.
The figure of 325 (if we conservatively divide that Police Federation warning in two) suggests that there is a strong enough cadre of recalcitrant republicans out there to keep the 'war' going.
Almost 13 years after the Omagh massacre, we must finally admit that we are living in the era of a second 'long war'.