The soldiers arrived before daybreak.

The week before they had held a funeral here for one of their men killed in a clash with militant leftists who had been gradually taking political control of the area. Not one civilian turned out for the rites for the dead soldier.

Now the troops were back to break up what Prime Minister Suleyman Demirel's right-wing government claimed was a "liberated zone" -- a commune imposed on the townspeople by militants belonging to the extreme communist faction called the Dev Yol.

A curfew was announced from the minarets of this fishing port of 30,000. Then, at daylight, armed police officers assisted by masked informers started a house-to-house search. (The informers themselves were rightist terrorists wanted by the law.)

The police encountered no resistance. More than 400 people, most of them teen-agers, were dragged from their homes, loaded into trucks, and taken to the state-owned Fish and Meat Aurhority slaughterhouse and warehouses for interrogation.

Mayor Fikri Sonmez, a highly respected figure who the authorities claimed was the head of the commune, was among those detained. The government is silent on his fate, but a noncommissioned medic said he was seen lying in a coma after being knifed and beaten by the police who captured him.

"They didn't know what they were doing," said a shopkeeper. "They let all the militants run away and rounded up all the innocent kids."

A few hours before the Army arrived, the communist Dev Yol activists reportedly gathered their arms and escaped taking refuge in the Black Sea mountains that extended for more than 900 miles along the coast.

In a small, shabby lobby of a hotel near the square, a 16-year-old auto mechanic who had just been released from 24 hours in detention recounted his story.

"We slept on top of one another, all 400 of us," he said. "No food, no open windows. They took us down to the basement in twos or threes for interrogation. There were four policemen. They beat us up, shouting, 'Talk, you sons of bitches from Moscow!" They were sweating as much from beating us that some of them had to take off their tunics."

The violence at Fatsa is but another symptom of the deterioration of political life in the Turkish countryside. Turkey's many government crises and its prolonged economic slump have emboldened all extremist factions many areas by force of arms. Even martial law has been ineffective in suppressing the extremist adventures.

In "liberated" places -- their exact number is not known -- citizens are often almost captives of armed terrorist bands. Murders are committed in the open. District governors, police chiefs, judges, prosecutors, teachers and the like are often forced to do what they are told.

State authority is to a large extent exercised by whatever group does the liberating. Opponents are either subdued, forced to leave or murdered.

While the extreme left is splintered in Turkey, the extreme right is loyal to Alparslan Turkes, chairman of the Nationalist Action Party. With 16 members in the 450-member National Assembly, the party is Turkey's fourth largest. But in reality it is much stronger. The party is one of two that keep Demirel's minority government in power. In exchange for this support, Demirel appears to have allowed the militants supporting Turkes to become a state within a state.

Demirel seems to believe that the only way to deal with the spreading power of communist groups like Dev Yol is to unleash Turkes' supporters.

When the prime minister took office eight months ago he declared that "the buffoonery" of the liberated zones "will come to an end."

However, apart from sending the Army to Fatsa, he has done little.

Bulent Ecevit, the social democratic opposition leader, maintains that the government is protecting rightist terrorists and will not move against them.

Fatsa became a "liberated zone" after the municipal elections eight months ago. Backed by Dev Yol, one of the strongest of the many illegal communist factions in Turkey, Sonmez, a 45-year-old tailor, became mayor.

Almost everyone in Fatsa credits Sonmez with important reforms. "In eight months he did more for Fatsa than all mayors put together in 20 years," said one of his former adversaries, a Demirel supporter.

He increased municipal revenues, built new roads, taxed the rich and cleared the streets of mud and dirt.

The majority of the people, especially the poor, were happy," the former adversary said. "Not everything he did was legal but things were getting done."

But Dev Yol "had ambitions beyond the municipality," one resident said. "They started extorting money from the rich to buy arms. They established people's courts and people's committees. They commandeered people's cars. They started saying that there was no need for the state."

Then people started getting beaten up in alleys and shot in public. There were robberies. Civil servants and rightists who disagreed with Dev Yol were forced to flee. Dev Yol activists established armed control in 90 of the 100 villages administered from Fatsa.

Finally the incident occurred that brought an end to the commune of Fatsa. On July 2 there was a clash in a nearby village square in which a Dev Yol activist and a noncommisioned Army officer died. Barricades went up all over Fatsa and many of its surrounding villages. It took 10 hours for soldiers to carry the body of their comrade the 19 miles up the obstructed road to Fatsa.

In Fatsa, all the shops were shut and a large crowd was attending the funeral of the dead militant. Nobody showed up at the funeral service the soldiers held in the town square. The Army returned in force a week later. As usual, its presence was sufficient to establish law and order.

The Turkish Army's impartiality and integrity is beyond dispute. It is probably the last remaining national institution that has managed to stay above the terrorism splitting the country into enemy camps and sowing the seeds of a civil war. Gen. Kenan Evren, the chief of staff, and his colleagues are gloomy about the situation but appear to believe that terrorism must be fought through legal and democratic means.

These means, however, have not proved effective. The Army is in charge of law and order in about half of the country where there is martial law. But other state institutions have become so eroded or partisan that the Army has achieved little. The undeclared civil war between the left and right, in which the politicians are taking sides, appears to have progressed too far to be stopped.

"Either we will slaughter them or they will slaughter us," said a Fatsa secondary school pupil, who did not look more than 15. "That is the only way this problem is going to be solved."