THE HOLDUP IN putting into effect the Good Friday (1998) Irish peace accords has led the British and Irish leaders, Tony Blair and Bertie Ahern, to set a "deadline." If by June 30 the Catholic Republicans and Protestant Unionists of Northern Ireland have not implemented the agreement, says Mr. Blair, then "we will have to look for another way forward." A limp deadline that. But what else can well-intending friends of peace do except to exhort the parties and nudge them along the way.

The outstanding issue, disarming or "decommissioning" illegal arms on both Irish sides, has been confounding negotiators for more than a year and has been "debated to death," in Mr. Ahern's words. The idea, a good and necessary one, is to confine all arms to instruments of a single Irish democratic political authority. The Unionists, being in a majority, reasonably could expect to lead a state authority and are not stressed, seem even content, to leash lingering Protestant terrorist squads.

The Republicans are in the harder position of -- some of them -- wanting to preserve a military capability, even though it is an illegal and terrorist capability, in order to maintain a broader set of military and political options. Others see their reluctance, rightly, as a refusal to give the signal that the war is done.

The Republicans' Sinn Fein, political wing of the violent IRA (Irish Republican Army), claims to have no responsibility for the IRA's policy. Tony Blair replies: "No one will believe that a party with a close connection with a paramilitary group could not bring about decommissioning."

Yet many will believe that some political compensation is due the Republicans in return for taking the risk that the Unionists will pocket a Republican act of decommissioning and then crimp Republicans' access to the Good Friday arrangements for power-sharing. The distrust does not relieve them of the necessity of moving together into the final steps toward peace.