It is almost certainly no accident that those responsible for yesterday's van bombing chose a mainly Protestant village on the verge of the Armagh/Craigavon area where dissident loyalists opposed to the peace process are active.
Loyalists in north Armagh around Markethill see themselves as living in a frontier alongside an area of militant republicanism running from south Armagh to north Monaghan.
Among the extreme loyalist figures who have emerged from this area is Billy Wright, the dissident loyalist at the centre of the militant Drumcree protests and who is now in the Maze Prison.
Last year, Wright, whose family moved from the north Armagh countryside to Portadown in the 1970s, split from the mainline loyalist paramilitaries and along with some other figures set up the Loyalist Volunteer Force (LVF). The LVF is opposed to the talks process and the broader peace process which has surrounded it.
The group was responsible for a number of sectarian assassinations in rural areas of the North, including two this year.
Its corresponding organisation on the republican side is the group calling itself the Continuity Army Council (CAC) of the IRA, or simply the Continuity IRA, which is believed to be the paramilitary wing of the splinter political group, Republican Sinn Fein (RSF).
While RSF denies it has a paramilitary wing, there are clear connections between it and the group. An RSF ardchomhairle member, Michael Hegarty, is serving 10 years' imprisonment for possession of 1,000 lb of home-made explosives near Enniskeen, Co Monaghan, in October 1995.
The RSF news sheet, Saoirse, has repeatedly carried statements and stories about the CAC, whose first appearance was around three years ago when four men fired shots over the grave of the veteran republican, Gen Tom Maguire.
In an environment where the mainline paramilitary organisations in the North, the IRA, UDA and UVF have moved towards peace, the small dissident groups such as the CAC and the LVF are developing something of a symbiotic relationship.
While the CAC and LVF appear to pursue diametrically opposed political objectives - one seeking a united Ireland; the other fighting against it - each is likely only to benefit from the other's acts of violence.
Any bomb attack now by extreme republicans, paradoxically, has a more damaging effect on a nationalist leadership seeking accommodation with unionists and the British government.
The bombing in Markethill also raises the risk of provoking retaliation from the extremes of loyalism.
This could translate into further acts of violence by the LVF against nationalists or even nonpolitical Catholics.
Acts of violence against Catholics could cause a groundswell within the Northern nationalist population for further retaliation, which could further destabilise the Stormont talks and the broader peace process.
The CAC has attempted this before. In July 1995, while the IRA was on its first ceasefire, it blew up a Protestant-owned hotel, the Killyhevlin, outside Enniskillen, Co Fermanagh. The attack took place during the height of the loyalist blockade of much of Northern Ireland during the first Drumcree stand-off.
The Killyhevlin hotel was evacuated only seconds before that bomb exploded and injuries were avoided.
Last month, the CAC attempted to bomb another Protestant-owned hotel in Fermanagh on the shores of Lough Erne at Carrybridge. This attempt and two or three other attempted bombings in Belfast and Derry by the CAC also failed.
The CAC almost certainly derives its bomb-making abilities from people who learned these skills with the Provisional IRA in the 1970s. The types of CAC bombs recovered since the attack on the Killyhevlin are said by senior security figures to bear close resemblance to the car and van bombs constructed by theProvisional IRA up to the early 1980s.
The CAC bombs are quite unlike the bombs constructed by the Provisional IRA since the mid1980s and forensic examination of the remains of the device should establish this within weeks or even sooner.
Even though the CAC is clearly not a big organisation, its membership is managing to escape detection. Only in the past two weeks, senior Garda sources expressed concern that the CAC would mount an attack in the North.