The soldiers smear black paint on their pale faces, the way combat troops do when going to war at night. Except here, it is broad daylight and the scene is not some South American jungle but the streets of Chile's capital.

The black faces have been a new, terrorizing twist since late last month, when Gen. Augusto Pinochet began dispatching Army units to Santiago's poor neighborhoods. In raid after raid, patrols have kicked down doors, ransacked dwellings, rounded up people for identity checks, then stamped "reserved" or "secret" in red on the hands of those who should not be detained again.

The sweeps, the most extensive since the declaration of a state of siege two years ago, have seemed intended not just to counter terrorist attacks, as the government said, but also to give a starkly negative reply to the broad-based civilian groups that have called for an accelerated transition to democracy.

Despite a public plea last week from the head of Chile's Roman Catholic Church to stop the searches, they have continued, underscoring the polarization between the repressive military government and the violence-prone extreme left that has paralyzed Chilean politics.

In the middle is the vast majority of the population. According to independent polls, only a fifth of the population still supports Pinochet. About the same number say they are indifferent. The rest clearly want the general out and democracy back after 13 years of dictatorship. But Chile's large and varied cast of civilian politicians has yet to agree on a detailed transition program that would satisfy the armed forces.

Among opposition leaders, foreign diplomats and civilians who have good contacts with the military, the consensus is that the military and the police services have decided to stand behind Pinochet until 1989, when the constitution says a presidential candidate will be chosen by the ruling military junta and subjected to a plebiscite. It is believed that Pinochet would like to be that candidate.

At the same time, senior military officials are increasingly worried about damage to the institutional prestige and morale of the armed forces that could be done by keeping Pinochet in power much longer.

"The forces are concerned about their professional future," said Federico Willoughby, a former government spokesman with friends in the military. "A young officer or soldier would like to see his institution moved out of the political fight and devoted to its conventional role in a democracy."

Two or three junta members -- including Air Force Commander Fernando Matthei, Navy Commander Jose Merino and Police Chief Rodolfo Stange -- are said by Chilean and foreign sources to be inclined to drop Pinochet in 1989. Only the fourth junta member, Army Lt. Gen. Julio Canessa, can be counted on, out of military and personal loyalties, to back the general for another term.

But just how the junta will respond should Pinochet refuse to step down -- whether officers will risk an open split between the Army and the other armed forces -- is the subject of speculation.

Before surrendering power, military commanders are looking for at least credible assurances from civilian political leaders that the Communist Party will not get into the government and that the armed forces will be protected from a campaign of political vengeance.

Opposition groups took a step in this direction last August, when 11 major parties signed a National Accord that excluded the Communists and promised no human rights trial in retaliation against the military. The accord, which also urged direct elections and the restoration of political freedoms, was to be a kind of blueprint for Chile's future, a democratic alternative to Pinochet's plan.

But disagreements among the signatories about specific aims and tactics broke out soon afterward. The discord merely reinforced the military's conviction that the opposition is still too splintered to receive a transfer of power.

Pinochet rejected the accord as too vague and incomplete and, in December, told Cardinal Juan Francisco Fresno, who helped draft the agreement, that "the page has already turned," meaning he did not want to discuss it. Last month, the 70-year-old general reaffirmed his opposition to changes in the 1980 constitution, a document widely seen as conceived by Pinochet as an instrument to keep himself in power until at least 1997. The president has suggested that it is too early to consider amendments because the constitution "has not been fully applied."

But openly contradicting Pinochet, Navy commander Merino told Chilean reporters that "there are certain articles of the constitution that merit restudy or modification before we hand over the government." As written, the constitution practically cannot be altered without the consent of the president, nor does it allow for much parliamentary initiative starting in 1990, when a partially elected Congress is to take office. Even should a civilian leader become president, the armed forces would effectively retain veto power over any law or policy that "compromises national security" or "gravely threatens the foundations of the institutional order."

Frustrated by Pinochet and not wanting to lose members to leftist parties advocating active resistance against the government, the centrist Christian Democratic and moderate Socialist parties have broken a temporary truce that followed the National Accord and rejoined the left in organizing university strikes, street protests and other forms of mobilization.

The Christian Democrats, Chile's largest political group, helped mastermind the gathering last month of professional associations and trade unions which, under the name of a National Civic Assembly, issued a long list of social demands and handed the government an ultimatum to respond by the end of May or face the threat of a general strike.

The meeting represented the broadest joining of organizations opposed to the government since the 1973 coup that brought Pinochet to power and recalled a similar protest drive three years ago. However, in contrast to the 1983 campaign, the current one is marked by a closer coordination between political parties and activist social groups.

So far, the government has issued no formal reply to the list of the assembly's demands, refusing even to accept a visit from assembly leaders who, in a symbolic gesture last week, simply left a copy of their declaration at the Interior Ministry's reception area.

Significantly missing from the assembly, in addition to farm owners and some trade unions, was big business. Not yet ready to break openly with Pinochet, the industrialists share with the military a view that the opposition is still incapable of guaranteeing a stable government. An economic upturn, brought on by falling interest rates and world oil prices, has made the business community all the more reluctant to take any upsetting political action.

"Politicians have so far been incapable of showing us a clear path," said Jorge Fontaine, president of the Confederation of Production and Commerce. "They've been talking of democracy but they haven't outlined a concrete program."

Right-wing parties oppose the social mobilization strategy. They say such mass demonstrations serve only to antagonize the armed forces and could easily turn violent. Willing to wait until 1989 for Pinochet's removal, the right favors more attempts at dialogue in the meantime. Some conservative politicians have begun floating the notion of a civilian candidate in 1989 named by the junta in a possible compromise between the military, opposition parties and the church.

Chile's right-wing groups took some encouragement in a meeting last week between Interior Minister Ricardo Garcia and the right-of-center National Union Movement, a signatory of the National Accord. Although it was interpreted by some as a government attempt to split the opposition, the meeting was seen by others as a budding effort by Pinochet to ease out of political isolation.