SHOCKED but not surprised is the best way to describe reaction in Northern Ireland to yesterday's shootings in Lurgan.

There are all the familiar feelings of horror over the stark and terrible deed itself - sadness for the families, especially the five children under 10 who are left without fathers and a sense of helplessness and apprehension as we gaze over the edge into the black hole called Drumcree.

When the IRA went quiet after the shooting of RUC officer Alice Collins on April 10th in Derry, every one assumed it was in part an election ploy. Now the elections are over, North and South, Sinn Fein has two MPs, one TD and a massively increased presence on the local councils. The gun can be picked up again without any electoral cost.

The republican movement has traditionally excused violence as a means of making political progress. There are those, even outside the republican movement, who argue that Canary Wharf brought about the Stormont multiparty talks.

What political aim lay behind yesterday's shootings? On a broad strategic and diplomatic level the incident appears to be an act of political vandalism: Lurgan constitutes a serious setback for those republicans who claim they want to eschew violence and pursue their aims by peaceful methods only.

Nationalist sources in the peace process say the British government was responding very positively to overtures from Sinn Fein. Considerable progress had been made and the scene was set for a successful third encounter between the British and Sinn Fein representatives.

There had been encouraging noises from President Clinton and the impending replacement of John Bruton by Bertie Ahern meant all the pieces were in place for the restoration of the peace process.

But the republican movement operates according to its own internal logic which allows it to carry out acts that appear to make little or no sense. The movement is, after all, a coalition of would be politicians who regard the United Irishmen as role models and another element which stems from a cruder tradition and harsher realities and whose activities are more reminiscent of the Defenders and other practitioners of grassroots terrorism.

The fact that yesterday's shootings took place a few miles from Drumcree cannot be regarded as accidental. With the contentious parade less than three weeks away, the perpetrators were clearly intent on sending out a crude signal: "Don't mess with us."

Unfortunately for the rest of us, those who killed the two RUC constables do not think in terms of high politics. They come from an environment which is seething with sectarian tension, where compromise is a dirty word and the niceties of the peace process appear to have little relevance.

Once again Northern Ireland steels itself for a loyalist backlash. Should the pleas for restraint go unheard, it is difficult to see how the loyalist parties can be allowed to remain in the Stormont talks. If they are excluded, then the penny candle may finally splutter and die. The nascent political trend among loyalists could be nipped in the bud. Everybody will lose, including politically republicans.

But even in the wake of yesterday's horror, the British government has not definitively closed the door. The line coming from Tony Blair and Mo Mowlam is no further talks "in these circumstances". The republican movement has carried out even more terrible acts than yesterday's shootings without having pariah status conferred upon it.

Unionists would like to see the republicans cast into exterior darkness. That was the thinking behind David Trimble's proposal to "pigeonhole" decommissioning so that his party and the SDLP could work out a deal among themselves.

The SDLP wasn't playing ball: the harsh reality is that Sinn Fein is now too strong for any deal to be cut without the republicans at the table.

SENIOR UUP sources expressed considerable apprehension over the possible influence Sinn Fein might have in the election of the new government in the Republic.

They are alarmed at the sight of Sinn Fein making its peace with the political system south of the Border all the better to pursue the "struggle" in the North.

The nationalist consensus which was about to be reestablished has received a severe jolt. So too has the credibility of the Sinn Fein leadership on the international political scene. There was considerable interest here in the statement by Gerry Adams that he was "shocked" by the shootings. It marked an escalation in rhetoric on his part although of course he did not and will presumably never bring himself to condemn any action of the IRA.

Meanwhile, security sources warn there may be worse to come and there may even be renewed IRA activity in Britain. Small wonder that Mo Mowlam was not her usual jaunty self yesterday. She looked depressed, even crestfallen. She has good reason to be. With Drumcree around the corner she could have used a little help and forbearance as she tried desperately to get a compromise between the two sides.

No doubt she will redouble her efforts but the IRA did the peace process no favours in Lurgan yesterday.