A group of former guerrillas, now briefcase-toting members of the National Congress, have become a prized display of Venezuela's unique transition from a backward country burdened by decades of dictatorship to a democracy now widely praised as the most stable of the region.

Led by Teodoro Petkoff, once a notorious guerrilla with a special talent for escaping from jail, more than a dozen former rebels now participate in congressional debates as members of the Movement Toward Socialism political party.

Of all Latin America's insurgent movements, Venezuela's is the only one that -- after conclusively failing -- now has former members alive and active in government. Their party is accepted as a legitimate rival by President Luis Herrera Campins' social Christian COPEI party and other opposition groups.

But the former guerrillas are quick to point out that the transformation of their movement is not one that is likely to be repeated in other Latin American countries.

"It has to do with the distinct characteristics of the country," Petkoff said, "its wealth, the refinement of its middle class, its capability for political subtlety. We learned that through fighting."

At the same time, the experience of the guerrilla leaders has given them a distinct political perspective on Latin America's crisis zones -- one that allows them to deplore Cuban "interventions," praise elections, welcome U.S. influence and back the insurgent movements of El Salvador and Guatemala and the Sandinista government of Nicaragua all at the same time.

"In the United States, I think people would imagine me as if I were Fidel Castro," Petkoff said in a recent interview, reclining in an office chair below posters promoting his high-profile campaign for the Venezuelan presidency. "But we have gone through a long process from that."

For Venezuelans, the story of the change from the dictatorship of Marcos Perez Jimenez in the late 1950s to a fragile democratic coalition government battered from both the left and the right has much to do with Castro, his appeal to a generation of Latin American youth, and his relationship with Venezuela's own patriarch, Romulo Betancourt.

Betancourt's new democratic government backed Castro's rebel movement in Cuba in the late 1950s, and only three weeks after taking power in 1959, Castro came to Venezuela. In Caracas, he delivered a stirring message of revolution that won over the country's restless student movement and decaying Moscow-oriented Communist Party as quickly as it alienated him from Betancourt, who insisted on slow democratic progress and good relations with the United States.

Within two years, as the Venezuelan government plodded toward reform while attempting to prevent coups from the military right and the dictator's old allies, Venezuelan leftists, impatient for change, embraced a Castro-style guerrilla movement, and were quickly supplied with arms and training by Cuba.

The fragile Venezuelan government reacted with force. Its partner was the Kennedy administration, which, just beginning the Alliance for Progress aid program for Latin America in reaction to the Cuban revolution, sent about 120 military advisers to Venezuela, turning the country into what one U.S. official described as a virtual laboratory for the counterinsurgency warfare techniques then being developed.

But U.S. military aid, these former guerrillas say now, had little to do with the downfall of their movement. Instead, said Pompeyo Marquez, who was taken from the Venezuelan Senate and jailed in 1964 only to be reelected in 1974, "it was our own political and tactical errors. We just didn't understand the reality of the situation in Venezuela."

What made Venezuela different from the nations where guerrilla movements have grown was an economic and social structure unique in the region, Venezuelans say. As a colonial outpost for the Spanish, Venezuela did not develop a strong class structure in its early history and remains a relatively mobile society, without many of the traditional barriers to social advancement of other Latin American societies.

More importantly, Venezuela became a founder of the Organization of Petroleum Exporting Countries in 1960, and since then oil wealth has poured in at sometimes astonishing rates, raising the country's per capita income to the highest in Latin America and blurring distinctions between rich and poor.

For some Venezuelans, this economic factor provides the explanation for the country's singular success with democratic government, just as the economic stagnation of the last several years could spell its doom.

"The conditions were not right for the guerrillas here because there wasn't anyone in Venezuela who didn't improve his standard of living in the '60s and '70s," said one television commentator.

"Our test will come in the 1980s, when people's lives are not improving, and they start resenting the social gaps."

But the leaders of Petkoff's party also give credit to the Venezuelan government's adherence to democratic procedure and relative lack of human rights violations.

"It quickly reduced us to the corners of society," said Luis Bayardo Sardi, the party's foreign policy director and a former guerrilla activist.

"It was a civilian movement that could generate a transition without large problems, it could point to us as a foreign-backed influence and it was never menaced itself by the United States -- just the opposite," said Marquez. "It was an actively participative democracy, and where there is a democratic government there just isn't room for an armed movement."

The Venezuelan guerrillas failed in an effort to disrupt elections in 1963, and, by 1967, the armed movement in the countryside had been crushed by the Army, never having won much popular support.

Leaders such as Petkoff and Marquez continued to slip from jail to clandestine activity, but they say they knew their cause was a failure. Then, in 1969, President Rafael Caldera, a Social Christian, moved to make peace with the demoralized movement by offering amnesty, release of prisoners and safe passage out of the country in exchange for a renunciation of violence. The guerrillas quickly accepted.

"It was a real show of political intelligence by the government," said Freddy Munoz, a Movement Toward Socialism congressman. "They could have moved to stamp out the movement altogether, but then there would have been much less possibility of internal peace and democracy."

In 1971, Petkoff, Marquez and many of the other former armed leftists joined to form the Movement Toward Socialism and participate in elections. By now, a fundamental plank of the party's platform is, as Petkoff puts it, "that the defense of democracy is an essential value of a Socialist program."

The group's experience has caused it to take a somewhat critical view of armed leftist movements elsewhere in the hemisphere. Having broken openly with Castro, the party now argues that Cuban material support for the guerrillas of El Salvador, for example, is a mistake.

Citing the Venezuelan guerrilla movement's own experience, Marquez argues that Cuban support for a nationalist group quickly leads to charges of intervention and the creation of a "block" to stop it, usually with U.S. military aid.

"We are against any kind of intervention," he said. "And we learned this ourselves. It cost us blood, tears and suffering."

At the same time, however, the party openly supports the guerrilla movements of El Salvador and Guatemala, and has attacked sharply U.S. and Venezuelan support for those countries' governments.

"We support a democratic process in those countries," Marquez said, "but you can't have a democratic process in the middle of a civil war, with a government that is liquidating social and human rights."

Unlike other Latin American leftists, however, the Venezuelan Socialists are not hostile to the role of the United States in the hemisphere, and in fact are now preparing a paper meant to prove, as Bayardo Sardi said, "that a socialist change in Venezuela would not be a threat to Venezuelan democracy or the interests of the United States."

This mix of views has won the Venezuelan leftists both the enmity of Castro and other Latin leftists and attacks by Venezuela's more traditional party leaders. Although the Movement Toward Socialism is the third-largest party in Venezuela and won 10 percent of the vote in 1979 nationwide municipal elections, its leaders say they never have overcome their image as former guerrillas with the voters.

Petkoff now says, however, that electoral failures will not send him back to the mountains.

"We have gone through a change," he says. "I believe democracy now is a value in itself. After all, it existed long before capitalism came about."