Under the cover of a cold Southern Hemisphere winter night, 200 Paraguayans recently ''roasted'' Gen. Alfredo Stroessner while staging an asado, a typical South American barbeque.
The oratorical tongue-lashing of Paraguay's strong man, who has ruled longer than anyone in the Western Hemisphere, would have been unthinkable a year ago. It reflects mounting political and social unrest here, as well as the impact on Paraguay of next-door Argentina's return to democratic rule.
General Stroessner, who today celebrates 30 years in power, has seldom seemed fazed by criticism. In fact he has seldom allowed it. But of late his critics seem to worry him. The small but well-organized National Accord, the opposition umbrella group that staged the roast, seems emboldened. The Roman Catholic Church is hectoring the generalissimo to seek a dialogue with the opposition. The United States Senate and State Department have protested his closing of the prestigious opposition newspaper ABC Color, shut down five months ago. This blast from the Reagan administration really hurt, foreign observers here say.
Police were kept at bay from last week's ''roast'' because Buenos Aires Mayor Julio Cesar Saguier, an American envoy, and at least a dozen Latin diplomats were present.
But the following day, the official government daily, Patria, castigated the National Accord, calling its members ''political reprobates'' and ''democratic deserters.'' And it accused the event's organizers of ''mental colonialism,'' an apparent attempt to exploit local resentment dating to colonial times, when Buenos Aires was the seat of the Spanish viceroyalty of La Plata. At that time, Paraguay was one of the viceroyalty's most backward provinces.
That such verbal pyrotechnics were loosed in a country where the independent press is muzzled and the opposition constantly harassed is reflective more of regime overkill than of any real threat to Stroessner's power, many foreign diplomats here say.
At the same time, there is recognition that Argentina's democracy has had an impact on Paraguayans. ''Argentine democracy is the greatest thing these people (the oppostion) have going for them. If Argentina sours it will be a disaster here.''
Stroessner's style, a mixture of populism, patronage, and repression, is typical of the governors in this country that has really never known democracy.
In the 173 years since independence, Paraguayan history has been one of coups , insurrections, and wars. Only seven contested presidential elections have been held - six, widely believed to be fraudulent, under Stroessner.
''We are a country of roughnecks, and so we have to be tough, too,'' said Esquiel Gonzalez Alsina, editor of the Patria. ''We have established a singular state, one of order, tranquility, and progress.''
Stroessner's power rests on the twin pillars of his Colorado Party and the armed forces. In Paraguay, access to social services, municipal licenses, university admission, and government jobs and contracts depends to a great extent on one's standing with the party, which is organized with a military-like heirarchy. Dissent often means economic reprisals against even uninvolved family members.
The general, sometimes called ''the durable dictator,'' carefully tends his populist image by inaugurating schools, attending weddings, and cutting ribbons at public works projects across the country. His speeches are frequently in Guarani, the Indian tongue spoken by most of Paraguay's more than 3 million people. Although Stroessner no longer arrives for work at the presidential palace at 5 a.m., he gets there by 7:30.
The general still presides over the 22,000-man armed forces, and military officers are required to belong to his Colorado Party. Military leaders retain a reputation for strong-arm tactics, although no one seems to see bodies floating in the Parana River anymore (a frequent occurence until recently).
Diplomatic sources say high-ranking military men preside over a brisk trade in whisky, cigarettes, stolen cars, and narcotics, the value of which is estimated at more than the total of the nation's legal exports.
The flourishing black market is a contrast with the ailing traditional economy. In the 1970s, Paraguay led Latin America in per capita income increases; they sometimes were larger than 10 percent a year. But the Itaipu Dam , the world's largest hydroelectric facility, built jointly with Brazil, proved to be a boondoggle for the regime.
Energy sales were expected to provide easy income for the government, and in fact it provided employment for some 15,000 Paraguayan construction workers. But the vision of easy income has blurred. Now it seems there may be too much energy. The financial future in energy seems cloudy, too. Besides Itaipu, a joint dam project with Argentina is starting.
The nation's traditional exports - cotton, lumber, and meat - also face a depressed market. The gross national product dropped by 10 percent last year, diplomats here say.
Against this background of economic decline, worrisome structural imbalances also are emerging, as reflected in last year's fiscal deficit of $160 million and a commercial trade shortfall of $230 million. For more than 25 years (1954 to 1980), the guarani remained anchored at 126 to the dollar; now it is 423 and rising. Paraguay's foreign debt is estimated at more than $2 billion, and financial analysts here say it may be forced to seek help from the International Monetary Fund.
''They should have gone to the fund already,'' said one diplomat. ''The financial crunch is a problem waiting to be discovered.''