But there is equally no doubt, as the Omagh bomb graphically illustrates, that even a mere handful of determined activists can cause appalling loss of life as they battle on in their quixotic quest to drive the British out of Ireland.
The following weeks will show whether they will succeed not only in filling coffins with the bodies of innocents but also in destabilising a peace process which has cut the death-rate and delivered new hope of lasting political progress.
The Omagh carnage will certainly test that process to the limit. The British and Irish governments will hope the communal conclusion will be that only the peace process stands any real chance of putting an eventual end to such attacks.
Those responsible were almost certainly part of a motley collection of republican dissidents opposed to the peace process. Originally three separate groups, they have in recent months formed a loose confederation, trading information and technology.
The first of them, the Irish National Liberation Army, has been in existence since the 1970s, carrying out killings such as that of Conservative MP Airey Neave in 1979. Although it has been in decline in recent years, its high-profile assassination last Christmas of the loyalist leader Billy Wright showed it remains dangerous. That killing triggered off a wave of retaliatory loyalist killings: the security forces will be fervently hoping that yesterday's attack does not have the same effect.
The second group in the federation, which styles itself the Continuity IRA, has made its presence felt in recent years with a series of bombings, most often of town centres. It had its origins in a split within the IRA and Sinn Fein in the mid-1980s, when a small group of republicans broke away in protest against the developing peace process. They claimed then that the IRA and Sinn Fein would eventually "go political" and lose sight of traditional republican goals.
The third group, which calls itself the "Real IRA", has emerged within the past year and has similar objections to the direction of republican policy. Its genesis lay in the resignation of five members of the IRA's executivelate last year. They too baulked at Sinn Fein's move into the political processes. They are the prime suspects for yesterday's attack.
Like the Continuity IRA they have bombed town centres, but they have also staged mortar attacks on security force bases, and in one case a gun attack on police. Although these two breakaway IRAs have caused much damage, they have not taken life prior to the Omagh attack.
There are believed to have been some defections of IRA members to these minor groups, principally to the "Real IRA". This is regarded as the most dangerous of the renegades in that those who formed it include a former "quarter-master general" of the IRA. He took with him key IRA personnel skilled in bomb-making techniques.
The small groups appear to realise that the prosecution of a low-level terrorist campaign stands little chance of eventual success. Rather, their main ambition appears to lie in a hope that the peace process will at some stage become de-railed, and at that point disillusioned republican activists will turn to them for alternative leadership. They want, in other words, eventually to take over the main IRA and send it back again to full-scale war.
Two effects could now flow from the Omagh bomb. The worst-case scenario is the beginning of the end of the peace process, leading the fledgling new deal to collapse. Or it could go another way, inflicting more damage on the renegades than on the process: it could stop their growth in its tracks. This is because this was a "dirty" bombing, claiming civilian lives, in an indiscriminate manner and on a shocking scale.
Other republican organisations learned over the years that, whatever the morality of inflicting civilian casualties, it had a huge effect on their own support. Republicans like to see themselves as soldiers and not terrorists, and Omagh is destined to go down in annals of the troubles as sheer terrorism.
The infliction of all those civilian casualties is not therefore going to win the admiration of hard-line republicans. Rather, it may well mean that the "Real IRA" will grow no more, and is instead destined for an arctic isolation.Reuse content