A key slowly turns in the deadlocked talks

THE third round of Sandinista-contra talks have ended in an apparent deadlock after three days of tense negotiations over the contras' terms for a ceasefire. The only two concrete acheivements of the talks were an agreement to meet here again June 7-9, and to extend until that date a 60-day ceasefire that would have expired May 30.

But the talks made overall progress - despite contra leader Alfredo C'esar's threats on the first day to end the process if no accord was reached, and despite Sandinista negotiator Gen. Humberto Ortega Saavedra's angry denunciation of the rebels on the last day.

At their final press conference May 28, the contras were subdued. Mr. C'esar, the chief rebel negotiator, said the third round of talks were ``neither a success nor a failure ... they are just not finished.'' But in even that, C'esar was more upbeat than on his arrival May 25, when he said the peace process ``was moribund and dying.''

Sandinista Defense Minister Ortega, was visibly upset at the lack of progress. ``We practicaly had an accord'' for an end to the war, General Ortega said. He blamed contra military chief Enrique Berm'udez and the Reagan administration in Washington for blocking a final armistice. Colonel Bermudez, on order from the White House, ``came to impede any accord'' from being signed, Ortega said.

But progress was clearly had in that the contras presented for the first time their list of demands for political changes they wanted before they will lay down their arms. This includes separating the Army and police from control by the Sandinista Front, opening an opposition controlled television station, abolishing the military draft, and establishing a constituent assembly to implement changes to the Constitution.

Further progress was made when the government - which at first denounced the proposal - incorporated the contras' demands into their original plan for a definitive cease-fire. The government was reportedly willing to meet all the contra demands, so long as the changes were discussed and implemented inside the National Dialogue between the government and all opposition parties.

That's where the talks hit a snag: not over the question of what changes are required, but when and how to implement them. The contras are demanding ironclad guarantees that the National Dialogue will not ``result in just discussion and no changes,'' said contra spokesman Bosco Matamoros. Another contra official said, ``We are not questioning the Sandinistas' power. But we want guarantees that change will happen, not just be talked about.'' The contras, he said, want the rules of politics and power to be ``fixed before'' they lay down their arms. Thus, the timing of the changes is the last stumbling block to a final armistice, he said.

The government is reportedly ready to make some changes in the Sandinista Popular Army, such as changing its name. How far they will go in relinquishing real control of it is uncertain - as are the other changes the contras want before disarming.

The government argues that to undertake such sweeping changes outside the National Dialogue and the National Assembly will undermine the internal opposition - which did not take up arms - and reward the contras for their armed struggle.

But despite the seeming deadlock of the last meeting, the contra official said he was ``certain we will sign [a final] accord'' at the June 7-9 meeting. Explaining his optimism, the official said: ``There will be no new proposals or themes introduced at the next meeting. So the 10 days in between will be used working out what still separates us so that June 7-9 will be a time for finalizing the final document.''