A year after peace talks between the government and leftist insurgents lit a beacon of hope for Salvadorans, it has dimmed to a glimmer, eclipsed by bloodshed and recrimination.

Statements from rebel leaders, government officials and diplomats here indicate that even if another formal meeting can be arranged at some point, both sides have become resigned to a long military struggle. The civil war is generally considered to have started with a military coup on this date six years ago.

The war now will be on a smaller scale, they predict, but still violent enough to leave El Salvador's 5 million inhabitants without the peace and tranquility their leaders all say they want.

President Jose Napoleon Duarte's bold gesture -- unexpectedly suggesting the talks and sitting down with rebel leaders last Oct. 15 in the mountain town of La Palma -- has produced political dividends, burnishing his peacemaker image and helping win his party a legislative majority in elections last March.

The Reagan administration seems to have shared the perception of flexibility, without ceding in its determination to keep El Salvador's rebels from gaining a share of power.

But two events have punctuated the anniversary of Duarte's initiative and dramatized the effects of a stalemate likely to continue unless Duarte and his U.S. backers or the insurgents and their Nicaraguan and Cuban allies depart from longstanding positions in the conflict.

One came in the attack last Thursday on the Salvadoran Army's main training base by guerrillas of the Farabundo Marti National Liberation Front, the alliance of five rebel armies. The attackers killed more than 40 soldiers, by Army count.

The guerrilla forces showed they retain ability to mount occasional direct attacks on the Army despite massive infusion of U.S. money and equipment that has reduced rebel actions significantly in the last 18 months and prompted some Salvadoran officers to start talking about victory.

The other event was the abduction of Duarte's daughter Sept. 10 by gunmen who demand release of rebel prisoners in exchange for her safety. Duarte sent two other daughters and a daughter-in-law to the United States yesterday after saying his family had been threatened anew. He has offered to release most of 34 prisoners listed by the captors. But nine cannot be accounted for, according to Communications and Culture Minister Julio Rey Prendes.

The kidnaping of Ines Guadalupe Duarte Duran, 35, and her 23-year-old friend, Ana Cecilia Villeda, thus has put new venom into the atmosphere between Duarte and his rebel opponents for several reasons, making more remote the prospect of renewing the peace dialogue.

Rey Prendes, Duarte's closest aide, said the abduction "has changed the rules of the game with respect to humanizing the war." In the hope that followed the La Palma meeting, both sides had talked of small, concrete steps to "humanize" the conflict as a way to foster agreement on more difficult political issues.

"This is a new development that we have to come back and analyze with respect to the position of the Farabundo Marti National Liberation Front," Rey Prendes added, working on the government's conviction that the rebel alliance sponsored the kidnaping.

In addition, the kidnapers' demands for a prisoner release created a potential new source of tension in Duarte's relations with the Salvadoran officer corps, which has to approve any decision to renew the peace contacts, cut off since a sour second meeting Nov. 30 in Ayagualo, just south of the capital.

The armed forces long have been the ultimate font of authority in El Salvador. But they have bowed to Duarte's leadership since his U.S.-backed election in May 1984. Despite reticence by some officers wary of setting a precedent, the high command also has endorsed the president's willingness to hand over rebel prisoners in exchange for his daughter.

This willingness could be shaken, however, by demands from the captors for detailed explanations of what happened to any prisoner on the list who cannot be turned over. Underlying the demands is an often repeated rebel charge that the armed forces have killed some rebel prisoners during torture.

Duarte, in radio conversations with the kidnapers, and Rey Prendes, in talks with reporters, have insisted that government investigations have turned up no trace of nine prisoners on the list.

Diplomats and other observers with long experience here said pushing the military hard on such investigations could disrupt a tacit undestanding Duarte seems to have worked out with the armed forces: that his government will not embarrass officers with prosecution of past human rights abuses as long as the military halts such practices in the future.

Upholding his end of the understanding could delay release of Duarte's daughter and expose him to new rebel charges that he condones the abuses despite his frequent proclamations to the contrary, the diplomats pointed out, while discarding it could endanger his support in the military.

Duarte has encountered no known trouble from the military over his gesture in La Palma a year ago, largely because the talks quickly bogged down in mutual charges that both sides were only using the dialogue to gain propaganda points and never approached genuine bargaining.

Ruben Zamora, a leader of the rebel movement's political wing, the Democratic Revolutionary Front, told reporters recently that the dialogue got nowhere because Duarte and his U.S. backers never really wanted to negotiate. Duarte has contended for months that this was the rebels' position as well, labeling the talks mere "tactics" on their part.

Rey Prendes said Duarte nevertheless had been on the point of agreeing to a rebel demand that the next round of talks be held publicly in El Salvador rather than privately in another country as sought by Duarte and U.S. diplomats. But even that procedural concession has now been thrown into doubt, he declared.