The politics of polarization. After four years of waiting for the ruling Christian Democrats to bring peace and prosperity, many Salvadorans are disillusioned. With presidential elections only five months away, the far right and the left are working hard to fill the void in the political center.

JUST as the new mayor, Armando Calder'on Sol, launches into a tirade about corruption and inefficiency in the government of Jos'e Napole'on Duarte, he is cut off by an urgent phone call from the chief of police. Mr. Calder'on Sol - a front-line warrior in the battle to reform the nefarious image of the right-wing Nationalist Republican Alliance (ARENA) - returns with startling news: The police just caught two of his employees selling promises of government jobs for $100 to $200 each.

``There's a crisis of values in every government institution,'' says Calder'on Sol, echoing the theme that, in March, helped him sweep past incumbent mayor Alejandro Duarte, the President's son. ``We're trying to create a totally new image. And if we don't do something about corruption, we're not going anywhere.''

It's quite a twist on history.

Ever since ARENA was founded by former Army intelligence officer Roberto d'Aubuisson in 1981, it has been known more for chasing down ``communists'' than corruption.

Mr. d'Aubuisson himself has been charged with leading right-wing death squads that bloodied the streets with up to 25 bodies a day in the early 1980s. US officials accused d'Aubuisson of arranging a machine-gun attack on the American Embassy here in 1981 and linked his associates to a plot to assassinate then-Ambassador Thomas Pickering in 1984.

The controversial ex-Army major is still the party's driving force, according to several diplomats who closely monitor ARENA. But he has lowered his profile since his 1984 election defeat, allowing the more moderate voices of Calder'on Sol and presidential candidate Alfredo Cristiani to woo middle-class voters and US policymakers.

The strategy has apparently worked.

ARENA overwhelmed the US-backed Christian Democrats in the March 1988 elections, winning 179 of the country's 262 towns and a majority of deputies in the 60-seat Legislative Assembly. And now, as it promotes reputation for clean, effective government, the far-right party seems poised to wrest the presidency from Duarte's party in elections next March.

The US administration has portrayed ARENA's election vic-tory as another step for a maturing democracy. Assistant Secretary of State Elliot Abrams says: ``I can't think of a better test than having a government in power run totally free elections and allow itself to lose them.''

Setback for US policy

But a wide range of foreign diplomats and political analysts here - including ARENA leaders themselves - consider the party's rise to be a stinging rejection of an American policy that has staked its hopes on Duarte's moderate Christian Democrats.

Even US officials concede that if d'Aubuisson played a key role in an ARENA presidency, Washington would have to reevaluate its deep commitment to El Salvador.

Since 1980, the United States has spent more than $3 billion propping up the political middle so that extremists on the right and left would not take power. The Central Intelligence Agency even pumped in several million dollars to ensure Duarte's 1984 election win over d'Aubuisson.

Duarte has notched some successes. Despite the country's current power vacuum and economic woes, the military has not responded with an old-style coup. The leftist rebels are finding it difficult to stir up social unrest. And even Duarte's leftist critics say more Salvadorans now respect the vote as the most effective method for change.

But even with massive US aid - and in part because of the exaggerated expectations it generated - Duarte has lost popular support. Indeed, pollsters here say the March elections were less a popular embrace of ARENA than an angry rejection of the Christian Democrats for failing to produce either prosperity or peace.

Voters disillusioned

For proof, the pollsters point to the fastest-growing group in the electorate: people who don't vote at all. More than 1.4 million voters cast ballots in the 1984 elections that catapulted Duarte into office; only 930,000 people voted in last March's legislative elections.

Like a negligent farmer, critics say, Duarte has failed to cultivate his government. He chose ineffective administrators. He let the misuse of US funds run rampant. And he failed to prevent a damaging internal split from eating away at his party.

But there were also enormous roadblocks. With his lofty goals of peace and reform, Duarte felt trapped between left and right. According to a close friend, his feelings urged him to address the needs of the popular working classes; but his reason told him to cater to the powerful - the Army, the oligarchy, and the US Embassy.

``Duarte created, in theory, a centrist government of reform and change, but he's just clung onto office,'' says a European diplomat, voicing the frustration of many Salvadorans. ``In the face of monumental challenges, he's retreated into the world of illusion. He has come to represent not reform but the status quo.''

Left joins political process

Several leftist politicians have returned after years of exile to try to capture the huge pool of disillusioned voters. They formed a small coalition, the Democratic Convergence - including the political ally of the guerrillas, the Democratic Revolutionary Front - to participate in the 1989 elections. But the leftist leaders have not re-nounced their ties to the rebels (see accompanying story).

The Christian Democrats' presidential candidate is a former planning minister, Fidel Ch'avez Mena. With heavy US backing, the colorless technocrat recently won a bitter power struggle with his freewheeling party rival, Adolfo Rey Prendes. But most political observers say Mr. Ch'avez Mena piled up a lot of political debts along the way.

``His hands are completely tied,'' says leftist leader Jorge Villacorta, noting that the candidate owes his biggest debt to the US Embassy. ``Ch'avez Mena is much more compromised with the US than Duarte ever was,'' he says. ``He'd make a good employee.''

ARENA'S `moderate' man

Ch'avez Mena's opponent in ARENA, businessman Alfredo Cristiani, is also a bit short on clout and charisma. As one European diplomat quipped: ``Freddy is very pleasant, very moderate, very mediocre - he'd make a good diplomat.''

Mr. Cristiani, a Georgetown University graduate, has impressed US policymakers with his soft-spoken manner and perfect English. The wealthy coffee grower says he wants to roll back Duarte's liberal reforms by returning the banks and export trade to private hands. But he also assails the US for bogging down the war effort with its ``human rights psychosis.''

Cristiani has attracted middle-class voters looking for a respectable alternative to the Christian Democrats. But critics say his policies would dangerously polarize the country, widening the gap between left and right, rich and poor.

``The only serious chance for stability is if Ch'avez Mena wins,'' a top Reagan administration official says. ``If Salvadorans want to continue European and North American support, they need Ch'avez Mena there.''

But several other US officials and Cristiani himself seem confident that as long as ARENA maintains a moderate image, the US won't slash badly needed economic and military aid. ``If we win a free election,'' Cristiani says, ``the US has no choice but to work with us.''

With ARENA running ahead in the polls, US officials here are scurrying around trying to help tame the party. But some officials say they still have a lingering fear that the inexperienced Cristiani will not be able to control ARENA's darker side. There are unsettling signs that Cristiani is not in charge.

Retired Col. Sigifredo Ochoa, ARENA's president of the Legislative Assembly, recently raised new concerns when he warned that any US attempt to impose Ch'avez Mena as president would be met with ``right-wing guerrillas.''

At the ARENA party convention Oct. 9, it was d'Aubuisson who wielded influence behind the scenes. According to a party official and a well-informed diplomat, his supporters pressured Calder'on Sol, the moderate mayor, to decline the vice-presidential nomination, leaving it open for a close d'Aubuisson ally.

It's not clear how the US would react to an ARENA victory. But just as Duarte's 1984 victory over d'Aubuisson removed El Salvador as a contentious US issue, so ARENA's rise is sure to put the country back on the American political map.

El Salvador's political left is a study in contrasts

Rub'en Zamora seems to thrive on contradictions.

On one hand, he is a driving force behind the Democratic Convergence, a coalition of leftist parties participating in the democratic process for the first time in 16 years. But on the other hand, the European-style Socialist keeps an alliance with the Marxist rebels of the Farabundo Mart'i Liberation Front.

One of the Convergence's priorities in the campaign for next March's presidential elections is to push for political negotiations, including the FMLN, to bring an end to the eight-year civil war. But statements by the rebels indicate they may yet try to sabotage the elections.

Mr. Zamora and Guillermo Ungo, the left's presidential candidate, returned from eight years of exile last year against the wishes of the FMLN to take advantage of the Central American peace plan and the political void left by the faltering Christian Democrats.

Organizing in rural areas in a bid to build a nationwide party, Zamora says they have found two sentiments among potential supporters: fear, given the thousands of political killings in the past eight years, and hope. ``Our task is to make hope predominate over fear.''

The leftist leaders admit that their continuing connection to the armed rebels has somewhat undermined their campaign.

Not only has it irked the United States Embassy and the Salvadoran government; it has also scared and confused some potential supporters. In several recent protest marches, more radical groups tied to the FMLN - prone to violence and provocation - have mixed with peaceful demonstrators. This has only ``given the Army an instrument to generate terror'' against all leftist supporters, one leader says.

The Army is not now engaged in the murders of leftist politicians, as it was in the early '80s. But the Army and government are carrying out an extensive psychological campaign to blame the Convergence for the destruction the FMLN wrought.

At a recent gathering of journalists, President Duarte asked: ``How are they going to justify their links with the FMLN? How are they going to explain it?''

Zamora says it is simple. ``The FMLN is an indispensable part of the political solution in this country. It would be a political absurdity to return to fight politically and break relations [with the FMLN].''

At this point in El Salvador, he suggests, elections alone will not resolve the country's problems, since no matter who wins, the real power rests in the hands of the Army. Zamora says political negotiations involving the Army and rebels are needed along with elections.

Also, by severing ties with the FMLN, a force rooted in the country's economic and political injustices, leftist politicians fear they would be reduced to a ``bonsai left'' - a decorative part of Salvadoran democracy continually pruned by intimidation.

For now, the Convergence is only shooting to finish third in the presidential race. That way, one of their members, most likely Zamora, would be appointed to a five-year seat on the three-member elections council - and play a key brokering role in running the country's future elections.