We must prepare for war if we're to build lasting peace
They haven't gone away, you know. In spite of all the unprecedented unity witnessed at the funeral of Constable Ronan Kerr, they still exist out there in the mists of Ireland.
Of course, we must be heartened enormously by the reaction to the young constable's death. Northern Ireland is a much better place today than it was before.
As a native of Tyrone, I never believed in my lifetime there would be such a magnificent coming-together in such a deeply-divided county.
A bit of that spirit existed in my childhood way back before the Troubles, but nothing to compare with last week.
Nothing to compare with thousands of GAA fans standing in silent salute to a police constable and applauding his memory. Nothing to compare to unionist, republican and nationalist, Protestant and Catholic, British and Irish mourning together.
It was the second time this year I felt like that about life in Tyrone. The cross-community sympathy extended to the GAA manager Mickey Harte on the occasion of his daughter's murder in Mauritius signalled the changing public mood.
The mourning for Michaela McAreavey told us the wind of change was blowing in a new direction and it turned into a gale-force for good at the constable's funeral.
So where are we now? Fiction is fast becoming fact. A British queen is soon to be welcomed to Dublin. Croke Park, the citadel of Irish nationalism, is opening its famous doors to her.
The memorial to the dead of 1916 awaits her presence and her wreath. Let's forgive if not forget. That's the mood of people everywhere from Tyrone to Tipperary.
Except for those beyond the Pale, who killed Ronan Kerr.
I would like to believe that they have gone away, or are going away, but the harsh security facts suggest that is not the case.
The operation to kill Constable Kerr was only one of nine serious dissident attacks in the first three months of 2011. Last year, there were 40 and the year before 22.
The heart wants to tell us it's over. The head tells us it's not, because out there hiding among the bushes of Tyrone or other parts of Northern Ireland and the Republic are people with mind-sets unfathomably prejudiced against peace.
Who are they? I asked a senior security source what kind of people he thought they were. He said they fell into two categories: the older, experienced terrorist and the impressionable, younger recruit. The latter might be weaned away from violence, the former is probably a lost cause.
The older guys are well-known to their former colleagues in the IRA and the wider republican movement, to people in their neighbourhoods and, not surprisingly, to the police as well.
Every now and then, they may be stopped and questioned, or even suspected of wrong-doing, but walk free because insufficient evidence is available to take them out of community circulation.
After years of terrorist experience, they know all the ropes. When to wear protective clothing which can be discarded after an attack.
How to use chemicals to wash themselves down and erase every trace of their terrorist behaviour. What to say when the police come knocking on their door or stop them in the street.
They believe they are untouchable and, in many cases, they are because they are protected by and can hide behind the liberal democracy in which we are fortunate to live in civilised western Europe.
If they existed in many other corners of the world, their feet would not touch the ground before they were accused, imprisoned, interned, placed under house arrest, or spirited away or killed by state forces.
Northern Ireland isn't like that anymore and because we don't want it ever to be again, we must put up with killers in our midst and find others way of isolating them. We're trying to forgive, if not forget. We're moving slowly and tentatively forward together for the first time.
We're just about past the point of no return. We can see a land of promise, but we need to be stoic and brave-hearted because they haven't gone away, you know.
If words of sympathy and condemnation were enough, it would be over by now. Instead we must be realistic.
We are locked in a long haul, a petty and pointless war of attrition between the people, their new police force and a twisted mind-set hidden in the mists of time.
Sadly, we must brace ourselves. We are proud of young Ronan Kerr, but he will hardly be the last casualty.