The bold wall paintings and fluttering marching banners reappearing in Buenos Aires are like defiant taunts to a failed military government.

"Popular socialism," they proclaim, "For the rights of the people," or, "Down with the dictatorship. Communist Party."

The display is startling for Argentines accustomed to a long campaign of repression against leftist political movements. This South American power, its armed forces once promised, would lead the way in banishing Marxist influence from Latin American politics.

Instead, after a decade of violence, Argentina's left appears to have returned to a familiar position in a country characteristically attracted by revolution but impatient with ideology.

The left "is out there, and it makes a lot of noise," said a socialist journalist. "But it isn't the base of a real movement."

With the approach of national elections and the return of democratic government, at least five leftist parties, including the pro-Moscow Communists, have met membership requirements for legal recognition. Meanwhile, the tactics--and existence--of the left appear to have faded as political issues in Argentina for the first time in a generation.

The result has been a fundamental change in the nation's unstable power balance. When the last presidential elections were held a decade ago, Marxist groups framed much of the political debate even as they moved toward a campaign of violence that became one of the largest in modern South America.

Then, the military coup in 1976 initiated a bloody government campaign of counterterrorism that left at least 6,000 dead and spawned a new authoritarian ideology based on combating Marxism.

Both the guerrillas and the armed forces are now discredited, and the long conflict appears to have settled--if only temporarily--into an exhausted stalemate.

"We have more possibilities now to create a dialogue and present an alternative," said Guillermo Estevez Boero, the presidential candidate of the Popular Socialist Party. "But the elections show the military accomplished part of its objective--it moved the whole political discussion to the right."

The shift in the role of the Argentine left has been shaped in part by its largest political parties. After years of polarization and violence, both the centrist Radical and populist Peronist parties have moved toward relatively moderate platforms and candidates for the Oct. 30 elections, isolating once-powerful factions on the left and right.

"The left has been buried within the Peronists and Radicals," who together are expected to win the bulk of the votes in the elections, said Mario Campora, a nephew of former leftist Peronist president Hector Campora. "The two parties have distributed between them a revolutionary force that is not represented by the candidates. The candidates are like Pepsi and Coke--they both are colas."

At the same time, the smaller leftist parties have had trouble winning recognition in a campaign that increasingly has become a race between two large parties.

"The leftists don't want to be involved in a small ideological party," said Roberto Cortes Conde, a political scientist. "They would rather work for one of the major candidates in the hope of having an impact."

For many leftist leaders, even the existence of democratic socialist and Marxist parties in the first political season after military rule is something of an accomplishment. Although leftist parties have had a long and sometimes distinguished history in Argentina--the first socialist party was formed in 1896--all were badly damaged by the guerrilla movements of the 1970s and the military's violent response.

While Argentine guerrillas were concentrated in two clandestine groups, military security forces arrested or abducted and killed thousands of other leftists during the late 1970s. Even the Communist Party, which denounced the guerrillas and publicly supported what it labeled "moderate" elements in the military government, suffered 107 "disappearances" of members and more than 3,000 arrests, party officials say.

Meanwhile, the political and military failure of the guerrilla groups, led by the Peronist Montoneros and Trotskyist People's Revolutionary Army, disillusioned many students and intellectuals with the left and alienated an already unconvinced middle class.

"The guerrillas won a lot of sympathy at one time, especially among students and intellectuals," said Luis Zamora, the presidential candidate of the New Movement to Socialism party. "That experience had a large effect on Argentine youth, to the point where there is a certain rejection of violence that extends to the left."

During Argentina's last democratic era between 1973 and 1976, student organizations were dominated by leftists of the Peronist youth movement, which in turn was closely tied to the Montonero guerrillas. Now, political analysts here say, the strongest student organizations may belong to the middle-class Radical Party, whose candidate, Raul Alfonsin, could be described as a Social Democrat.

Despite occasional military warnings of a revival of terrorism, the leftist guerrilla organizations remain inactive and apparently largely dismantled. No leftist group other than the 65-year-old Communist Party is receiving significant foreign aid, political sources here say, and many of the surviving guerrillas have joined political groups such as the Intransigent Party, a left-of-center splinter from the Radical Party.

With the long era of violence at least temporarily over, many leftist leaders see the potential for the formation of a broad democratic socialist movement in Argentina similar to those in Spain, Italy and France.

Party leaders point out that the leftist parties together have more than 450,000 registered members, and that 3 million to 4 million young Argentines remain uncommitted to the traditional party organizations.

"There is a process of searching for new alternatives," said Zamora. "People are beginning to turn away from the negative experience of the traditional parties."

And yet, the reborn leftist parties are now finding themselves entrapped by an old political problem--the attraction of the populist movement founded by former president Juan Domingo Peron.

Although the Peronist party spawned a left wing and the Montonero guerrillas in the late 1960s, its roots lie in right-wing corporatism along the lines of Mussolini's Italy and Franco's Spain and its vague populist ideology embraces a "third position" between "Yankees and Marxists."

At the same time, the Peronists still control both the leadership and the apparent popular support of the overwhelming majority of Argentina's labor movement. Thus, Argentine leftist parties have had to choose between attacking Peronism--and its blue-collar members--or seeking to support a worker-based party whose politics are often rightist.

This dilemma has led to an awkward scene of maneuvering by Marxist parties this year. All but Zamora's have hoped for an alliance with the Peronists, and preferably one that excluded all of the other leftist parties.

"There is a battle going on among the socialist parties to stake out the position as the first alternative to the Peronists," said Estevez Boero of the Popular Socialist Party, one of three socialist groups that claim the more than 40,000 members necessary to be recognized as a national party. "So any leftist alliance is very difficult."

The Peronists, for their part, say they have no interest in forming a coalition with other parties. Thus left out of serious electoral calculations, the leftist parties are now expected to win only 8 to 10 percent of the national vote, and pledge their votes in Argentina's electoral college to the Peronists, even without an alliance.

Meanwhile, they say, they can only hope that democracy will be more favorable to them than military rule.

"Our opportunity will begin with the new government and democracy," said Campora. "When we can work with full liberty of expression and without a state of siege, then we will know what can be accomplished."