For nine long years, guerrilla warfare by leftist rebels, a murderous opposition on the right, a weak democracy, and a tottering economy have kept tiny El Salvador in turmoil. A slender chance to end the war has raised its head, but sadly, that possibility may never take place.

Leftist insurgents offered in late January to lay down their arms and take part in a presidential election if the government agreed to a cease-fire, would start negotiations, postpone the March 19 elections five months in order to give the rebels a chance to mount a political campaign and give certain guarantees to leftist political groups.Those terms have prompted widespread debate in El Salvador and have gained considerable support from centrist and moderate elements. President Jose Napoleon Duarte, who first rejected the election postponement as unconstitutional, now is ready to accept the idea. The army has indicated it would go along with a cease-fire.

Even U.S. diplomatic officials, once only lukewarm toward the rebel proposals, now say they offer the "most significant opportunity ever for peace in El Salvador."

Yet the plan appears to be dying. Right-wing extremists, known by the Spanish acronym ARENA, turned thumbs down this week on any election postponement.

Since ARENA controls the National Assembly, the parliament of El Salvador, and is favored to win the presidency in the March election, any delay in the voting appears unlikely.

Duarte said that if the National Assembly refused the peace plan, he would favor a national plebiscite on the question of delaying the election. But again, with ARENA opposed and the presidential election less than three weeks away, such a plebiscite seems impossible.

Yet if the rebel terms are rejected and ARENA takes control of the presidency, a grim scenario will certainly emerge.

In the event their offer is spurned, the rebels have promised greater violence in a war where 70,000 - mostly civilians - have already been killed. And with ARENA as the top political power, there may be a return of the hated right-wing death squads.

Those developments, plus the disappointment of moderates who saw hope in the rebel plan, could lead to chaos in the tiny nation that has already suffered so much.

The U.S. has poured billions in aid into El Salvador, hoping to bring stability and prosperity to the country. All that effort may be wasted if this hope for peace is crushed and the old violent patterns are escalated.

If that happens, it is hard to see when there ever may be another opportunity to end the bloodshed. The rebels can't win, neither can the army. And the civilians remain caught in the middle.