PRESIDENT Jose Napoleon Duarte's peace bid to El Salvador's guerrillas reflects precisely the sort of vision and courage his supporters had hoped for. In a dramatically concrete speech at the United Nations, he offered to meet the commanders of five guerrilla groups next Monday at La Palma, a Salvadoran town sitting on the edge of a guerrilla zone. The commanders responded in a positive way, and it looks as though the first full-fledged opportunity for conciliation in El Salvador's brutal grinding war may soon materialize.

After he was elected last June -- in a contest in which the left did not take part -- Mr. Duarte put off the attempt at "dialogue" to which he had alluded earlier. The justification for delay was that he needed first to bolster the government's military capacities, with American help, and to demonstrate that he could adequately control the death squads -- which had ominously close links with the armed forces. Evidently Mr. Duarte decided he had made enough progress on both fronts to reach out to the guerrillas now. Perhaps he also felt that, with a strong political component now evident in the midst of the battle in Nicaragua, it was time to introduce a similar element in El Salvador.

The Salvadoran guerrillas have long argued, reasonably in our view, that the available security was insufficient for them to take up the Salvadoran government's offer to lay down arms and join a government-run political process. Mr. Duarte, however, has been moving to meet these objections. A prisoner exchange was recently conducted as a test; it was a success. The La Palma meeting has been further designed as a test of the two sides' readiness to holster their arms in a specific area. Mr. Duarte asks the guerrilla leaders to come unprotected and unarmed and says he will do the same. He has opened up the agenda in a way that finesses the guerrillas' past claim that they were being invited merely to join a government charade.

Memory is long and confidence short in El Salvador. Whether the hard right, which has not by a long shot lost all its connections in the armed forces, will stand still for a dialogue is no less a question than whether the Marxists in the guerrilla leadership will dare submit their political fate to the new elections Mr. Duarte has in mind. The wrong kind of signal from either side's foreign patrons could easily upset whatever process may conceivably get under way. It is a moment of great uncertainty, but of great promise too.