SUNDAY, after the bus bombing in Jerusalem - the third within nine days - Hamas announced that this was the final act of retaliation for the assassination of one of its leaders and that attacks would cease for three months pending negotiations for a cease-fire.
Then came Monday's explosion in Tel Aviv. Then Hamas talked again of a cease-fire that it clearly could not deliver.
Last month the Irish Republican Army carried out two bombings in London in the face of a 17-month cease-fire. The authors of the bombings emphasized that the attacks were on "direct instructions from the Army leadership." This suggested that the bombings were planned without the approval, perhaps without the knowledge, of its political arm, Sinn Fein.
What Israel and Northern Ireland appear to have in common is the emergence of breakaway groups within militant movements, die-hards determined to torpedo peace efforts and becoming more violent the closer peace seems to come.
In Hamas, the military wing known as the Al-Qassam Brigades, named for a martyr in an earlier war against the British, has spawned a splinter military group known as Pupils of Ayyash, named for Yehiya Ayyash, the bomb-builder assassinated in January. The Hamas militants have operated separately from the general protest movement known as the intifadah. Their fiercest assaults started after the 1993 signing of the first Israeli-Palestinian peace accords. Since then, they have struck 15 times, killing more than 150 people.
Their greatest success is that their terrorism has caused the suspension of the peace process and has forced Israeli Prime Minister Shimon Peres to retreat from his ideas of open borders and free movement. There is now security separation between Israel and the West Bank. The bombings have also virtually erased Mr. Peres's lead over the right-wing opposition in the May election. He may be obliged to postpone the election and ask the opposition Likud to join in a temporary "unity" government.
The Irish militants, known as "the hard men," are centered in the IRA's "Army Council," which came into being 25 years ago in a split over a cease-fire negotiated by more-moderate leaders. Remarkably, the IRA militants developed the suicide-bombing technique before Hamas did. In the 1980s, the IRA forced civilians, by threatening to kill their families, to drive cars with explosives to British Army posts.
In Northern Ireland and in Israel, terrorists find their reward in the disruption of the peace process. As President Clinton says, "they live for division and conflict." The dilemma is that pressing forward with a peace process becomes increasingly difficult in the face of the emotions that terrorism generates, especially among the Israeli people, whose legacy of Holocaust makes "safety" an overriding concern.