Despite Thailand's trappings of parliamentary democracy, its politics are still very much manipulated by the armed forces, a point firmly underscored by a neat political minuet here last month.

It was a period of unusual labor unrest, rumors of strife among senior military officers and a last-minute cancellation of a trip abroad by the prime minister.

They were the classic signs of a coup, the type of upheaval that puts American policymakers on edge as they follow the internal twists and turns of Washington's main ally in this troubled region of Asia.

With Vietnamese armies poised perilously close to Thailand's Cambodian border, the Thais' position as a window of Western influence in the turnmoil of Indochina has never been more in the spotlight.

As recent events demonstrated, however, the generals who run this country -- and Gen. Kriangsak Chamonon, the prime minister, in particular -- are firmly center stage.

Unlike other peoples of Southeast Asia, the Thais were never colonized and never fought a war of independence. Mass-based political movements never developed, and parties have remained small in membership and large in number. In most years since 1932, when absolute monarch ended, these parties have been denied a serious role in governing the country -- that was handled by a succession of generally benevolent military elites.

Kriangsak's government is the latest of these. He took power in a bloodless coup in 1977 and then called elections that reaffirmed his position. His performance in office had led foreign observers to label him Thailand's most enlightened soldier-politican. But a soldier-politican he remains and as such he suffers many of the same problems of his predecessors.

Details of last month's events remain unclear. The crisis, if it can be called that, began with a strike at the Thai tobacco monopoly, a government-owed factory that has exclusive rights to manufacture cigarettes in Thailand. By Thai standards, workers there have a strong union and, along with employes of other government-owed enterprises, are among the best paid in the country.

The workers walked out demanding a higher cost-of-living allowance and an investigation into alleged corruption in executive offices. Management agreed to negotiate and granted a few of the demands, but it then ordered everyone to return to work or face dismissal. It was an unusally strong response, diplomats believe. Riot police were called in and made a point of displaying automatic rifles and tear gas.

In the meantime, affiliated unions at two dozen other state enterprises -- including those providing electricity, transportation and telephones service -- threatened a sympathy strike.

Diplomats also pointed to the simultaneous reappearance of extreme rightist paramilitary groups in Bangkok -- more than 1,000 of the groups' supporters demonstrated outside the Soviet Embassy to protest the invasion of Afghanistan. Their conclusion was that Kriangsak was being challenged.

It soon became clear that the prime minister was taking a personal role in the strike negotiations. He publicly urged workers to return to their jobs and warned that four unnamed men would be punished for "instigating" the strike.

He called a meeting of senior government leaders, reportedly including most major military figures, to discuss antistrike strategy.

The following day, Kriangsak was scheduled to leave for West Germany to attend an international conference on farming (he is also minister of agriculture). He decided to send the deputy prime minister in his place.

His cancellation started rumors flying. The story most commonly traded in diplomatic circles was that certain military leaders had declined to go along with the prime minister's get-tough suggestions in the event of a general strike. This polite lack of cooperation reportedly made Kriangsak nervous that his future would be in question if he left the country.

The next day Kriangsak only fueled speculation by telling reporters there was no danger of a coup.

"The military coup d'etat is now out of date," he was quoted as saying. "The new generation of Thai-soldiers in walking the path of democracy. The commander-in-chief of the Army, Gen. Prem Tinsulanond, also denied a coup was in the offing.

Kriangsak soon found it necessary to publicly declare he would order an investigation into the source of a "scurrilous" report that he had wanted Prem to accompany Thailand's Queen Sirikit to the United States, where she was to undergo medical treatment.

Diplomats pointed out that the story's implication was that Kriangsak mistrusted Prem and wanted him out of the country.

Prem, lean and strikingly handsome at age 59, is the man Thais most often mention as the eventual successor to Kriangsak. Prem has repeatedly denied that he has political ambitions, but many analysts argue that no matter whether he wants it, the Thai political system will propel him toward a role in government.

On Feb. 11, Kriangsak effected a long-predicted Cabinet reshuffle to placate parliamentary critics and give new blood to the fight against faltering economic performance.

The new faces included several men labeled "technocrats" but foreign diplomats said the restructured Cabinet underscored the military's continuing dominance. Of its 37 members, 14 are from the armed services, including the prime minister and all three deputy prime ministers.

By month's end, the tobacco strike ended, with the workers returning to the factory having won a few of their demands. The sympathy strikes failed to materialize for reasons that remain unclear. At the same time, the coup rumors died down and diplomats expressed skepticism that Kriangsak's position had been under any real threat.

Kriangsak's personal relations with key military officers are said to remain relatively good, although his career as a staff man has left him without a group of officers who owe their own careers to his patronage.

Nevertheless, military officers who support Kriangsak hold key positions in the Cabinet and throughout the lower levels of government, and there is no rival who commands sufficient loyalty in the barracks to overturn a government.

His popularity in Parliament is less certain, but still sufficient to carry major votes. Late last year, Kriangsak defeated no-confidence resolutions aimed at several of his Cabinet members.

For all his base of power within the military, Kriangsak is not the average Thai's idea of a strongman. He came to power in 1977 overthrowing a harsh right-wing dictatorship; he has since moved to liberalize controls on the press and political parties and has quietly allowed many leftist students who had linked up with communist guerrillas to return to Bangkok.

Kriangsak is not considered to be a charismatic person and he is not enormously wealthy. One of his predecessors, for example, was on the boards of more than 70 companies. Kriangsak, in contrast, lives modestly for a man of his station and sometimes surprises visiting dignitaries by disappearing into his kitchen to cook a meal for them.

Kriangsak is not problem-free, however. The Thai economy was hit particullarly hard by OPEC's latest price increases, and inflation is believed to be running more than 20 percent. He must try to cushion this inflationary spiral while ordering unpopular price increases in gasoline, electricity and other necessities.