David McKittrick: What makes the loyalists angry is seeing the other side doing so well

It seems almost indecent to be considering the state of the Irish peace process so soon after such a hard-working young man as Daniel McColgan was despatched to a pointlessly early grave by the loyalists. Yet even in their grief the first, instinctive reaction of his teenage partner and the rest of his family was towards peace, as they issued an appeal against anyone retaliating for his murder.

It is this deep-seated human instinct that provides the process with its extraordinary inner strength: the sense that although lives are still being taken, the process has saved many more; the sense that enough should be enough. Violence such as this killing takes place against the background of the Good Friday Agreement, which has succeeded in providing a cross-community government encompassing David Trimble and Martin McGuinness.

Devolution may be punctuated by outbursts of political ill-temper, but it seems to be bedding in, supported by a clear majority within Northern Ireland and buttressed by huge goodwill from London, Dublin, Washington and indeed the rest of the world.

Republicans decommissioned some arms a few months ago and are increasingly immersed in politics, performing well at Stormont and hoping to make gains in the general election due later this year in the Irish Republic. This is not to say they have suddenly become pacifists: some of them are to be seen on the streets in Ardoyne riots, and the baseball bats are still wielded in the backstreets. The IRA, until last year at least, has been killing alleged drug-dealers at a rate of two a year.

Those who say this is absolutely non-democratic are absolutely right. Nonetheless the impression is strong that this is a movement in genuine transition, and that the republican killing-machine is gradually being wound down. There is, alas, years more work ahead, but this is not the Home Counties: it is Northern Ireland, where paramilitarism is endemic, where in some districts joining the local group is on a par with joining a football supporters' club.

The trouble is that while republicans delve ever more deeply into politics, the extreme loyalists have been moving in the opposite direction. Many loyalists never liked the Good Friday accommodation, partly because they oppose the idea of any accommodation. Nonetheless, many of them were prepared to give it a go, not least because it offered the chance of getting hundreds of loyalists out of jail,

The loyalist underworld groups sprouted political wings, sending representatives up to Stormont to meet the government. Some of those wings grew in strength, producing articulate spokesmen such as David Ervine and Billy Hutchinson. But the biggest group, the Ulster Defence Association, was never wholly enthusiastic about the process.

There is more to politics than decking out some UDA men in shirts and ties and giving them briefcases, and the organisation's political commitment was no more than skin deep. They liked the fact that the Good Friday Agreement got the boys out of jail, but they regarded its construction of a level playing field not as progress but as a string of concessions to Catholics. What they dislike most of all is the sight of the other side doing well.

The disenchantment with politics has led in recent years to a rise of loyalist violence, much of it the work of the UDA. Three-quarters of killings are now the work of loyalists.

On one level its most frequent targets have been Catholics, who have pipe-bombs thrown through their windows at dead of night. But when the guns come out, loyalists have mostly killed other loyalists, to the extent that Protestant feuding has been responsible for 40 per cent of all deaths in recent years. Most of this has sprung from the UDA's ambition to become top dog in the paramilitary underworld.

Next, localised factors came into play. The heartland of the UDA lies in the greater Belfast area, most particularly on the western side of Belfast Lough in a belt stretching from inner-city Shankill to suburban Rathcoole, the estate where Daniel McColgan was killed. It is here that lethal demography comes into play, for in many parts of north Belfast the Catholic population has been growing while Protestant numbers contract. The UDA regards all this as a double menace, watching with disapproval as nationalists make advances both politically and geographically.

Thus it is that parts of north Belfast became a battleground for much of last year – in particular at the Ardoyne interface, where an overflowing Catholic ghetto has met Protestant resistance.

At the beginning of the troubles, Ardoyne worried about being overrun by loyalist marauders in large numbers; today the loyalists see themselves as beleaguered and desperately trying to hold back an encroaching foe. In the mindset of local loyalists, their Ardoyne battle is part Alamo, part Stalingrad.

The UDA killed Daniel McColgan as part of their efforts to keep nationalism at bay. As a Catholic working in a loyalist estate, the message his death was meant to convey was pure sectarianism: keep out, keep away. The UDA does not rationalise or articulate things in this way, but he would have been singled out not as an individual but as a representative: an individual chosen almost by chance, to send the message that all Catholics are at risk.

These are base instincts, completely tribal, utterly sectarian. They are so primitive and so simple that they explain why some loyalists privately accept, as republicans never would, the label of terrorist. Yes, they say: this is about terrorising the Catholic community, which is the enemy. Thus it can be argued that the violence is aimed against the Good Friday Agreement, and the UDA and others would certainly celebrate if it should fail. But the gut sectarianism was there long before the Agreement, and so was competition for territory.

The north Belfast problem admits of no easy solution: it is, as somebody said a few centuries ago, like watching two Irishmen fighting with knives in a barrel. Even if the Agreement takes root and prospers, north Belfast seems fated to battle on for years to come, peace process or no peace process, sometimes claiming innocent lives such as that of Daniel McColgan.