HOPE FOR PEACE in Ulster is founded on an agreement signed more than two years ago between the British and Irish governments. The two nations promised to make a cooperative effort to fight terrorism, increase border security and improve the administration of justice in cases involving the continuing conflict in Northern Ireland. Within the past two weeks, however, Irish confidence in the administration of justice in Britain has suffered a serious blow, and the cooperative agreement has been undermined.

Late in 1982, six Catholics were killed by the predominantly Protestant Northern Irish police force, the Royal Ulster Constabulary. Five are known to have had paramilitary connections, but none was armed or committing a crime at the time he was killed. Four policemen were subsequently tried for murder, but their cases were heard without a jury, by so-called Diplock courts consisting of a single judge. All were acquitted, but during the course of the trials testimony acknowledging the existence of an official cover-up was heard. The outcry, both in Britain and in Ireland, was so strong that the Thatcher government ordered an inquiry into whether Ulster police had adopted a "shoot to kill" policy with regard to suspected terrorists. That inquiry took four years; its findings were announced Jan. 25.

Attorney General Sir Patrick Mayhew said that the RUC had not adopted a "shoot to kill" policy. Although there was evidence of police wrongdoing specifically relating to "attempts to pervert the course of justice," he said, there will be no further prosecutions. And for reasons of "state security," the entire report will remain secret. The Irish government expressed shock and extreme disappointment at this announcement and stressed to the British that public confidence in the administration of justice must be restored. This view has also been expressed widely in Britain.

Trust between the two governments has been badly shaken by the decision of one side to withhold information and to ignore acknowledged wrongdoing by the Ulster police. Americans, who have close ties to both countries and who have given financial as well as moral support to the peace effort in Northern Ireland, look for a renewed commitment to the goals of the Ulster accord and to a true partnership to ensure justice in the province.