or the first time in more than a decade, Italians vote this month in parliamentary elections without an array of urban guerrilla groups holding the nation's political system at gunpoint.

A large proportion of Italian politicians and newspaper commentators seem convinced that their country has emerged from a 15-year-long terrorist nightmare with its democracy intact.

Italy was long considered the Western European country most at risk from the general upsurge of terrorism in the '70s. Today all the available evidence suggests that, while some terrorist cells may still be in existence, terrorism as such is a spent political force.

Statistics issued by the Interior Ministry show that in 1978, the year that former prime minister Aldo Moro was kidnaped and assassinated by the leftist Red Brigades, there were 2,498 terrrorist attacks. In 1980, deaths from terrorism occurred once every three days on average.

The victims of terrorism (403 people were killed in terrorist incidents between 1968 and 1982 and 1,347 were injured) came from all walks of life. One in four were policemen. Apart from politicians such as Moro, businessmen and journalists were favorite targets. But the bulk of the dead and injured were ordinary citizens unlucky enough to be on a train or in a piazza when it was blown up.

The decline in terrorism during the last three years has been dramatic. Nearly 2,000 convicted urban guerrillas, including most of the leading members of the Red Brigades, are in prison. The last terrorist killing was in January, when a woman prison guard was gunned down in Rome.

The current disarray of the Red Brigades was reflected in an incident earlier this month when police captured two terrorists who had taken hostages at a bank in Rome. A third terrorist, a 23-year-old woman, escaped but later tearfully surrendered to the authorities because she had run out of hiding places.

A few days earlier, the wounding of a left-wing professor of labor law resonsible for hammering out an agreement over salaries between the government and the trade unions had fanned fears that the Red Brigades might be attempting to disrupt the elections scheduled for June 26 and 27. But that attack was dismissed by Italian President Alessandro Pertini as "the last swoop of a wounded wild animal," a judgment that seems to have been borne out by events.

The man with prime responsibility for the fight against terrorism, Interior Minister Virginio Rognoni, is also in little doubt that the Red Brigades have been "substantially defeated." In an interview here, he said that the terrorists had been "politically isolated" and "deprived of their former aggressiveness."

All this is in marked contrast to the situation in June 1978 when Rognoni was appointed interior minister following the resignation of his predecessor because of Moro's murder. At that time, the Red Brigades seemed to be acting with impunity. Commentators the world over were asking whether democracy could survive in Italy.

The year 1978 is now seen as a crucial turning point in the Italian state's struggle against terrorism. Moro's kidnaping and subsequent execution marked the height of the Red Brigades' power. With hindsight, one can see that it was also the beginning of their downfall.

"This was the most incredible act of terrorism in modern times, but the terrorists didn't gain anything by it," remarked Luigi Manconi, a left-wing sociologist who has studied the Red Brigades.

He explained: "By seizing Moro in broad daylight, the brigadisti demonstrated their technical perfection and the impotence of the state. But the government wouldn't negotiate with them so they killed Moro and, in doing so, antagonized many of their own supporters."

Manconi describes the Red Brigades as "ideological salesmen." Terrorism prospered as long as they could convince enough potential supporters that the problems of Italian society could only be solved by armed struggle against the state. It declined when it became obvious that they had no chance of achieving this utopian goal.

The growing disillusionment with terrorism as a means of change was cleverly exploited by a law passed in 1982 which promised "repentant" terrorists lighter sentences if they confessed. In Manconi's view, this effectively destroyed the image of the Red Brigades as a monolithic, revolutionary organization. Beset by gathering doubts, the brigadisti began confessing in droves.

The phenomenon of the pentiti, as the repentants are known, has given Italians a disturbing insight into the terrorist psychology. Once they take off their anonymous ideological masks, the former terrorists come across as decent Italian youths with pleasant manners, nice-looking faces and a fair degree of intelligence.

One wonders what drove these children of respectable families to kill and maim in pursuit of ideological goals.

Part of the answer was provided by the most prominent of the pentiti, Patrizio Peci, a former Red Brigades commander in Turin. During a television interview last month, he traced his own transformation into an urban guerrilla back to the feuding between left- and right-wing groups that followed the "hot autumn" of labor unrest in 1968.

Peci said the leftists started forming clandestine cells after being harassed by the police for bomb outrages that were later discovered to have been committed by fascists. As the organization grew, they became full-time brigadisti, living in secret apartments and drawing a salary of about $350 a month.

"I joined the Red Brigades because I believed this was the way to reach a better society," Peci told television viewers. "At a certain moment, I found I no longer believed. I understood that we were not succeeding in creating that minimum level of support which we hoped for."

The terrorists represented both extremes of the political spectrum. Until the mid-70s, it was the neofascists who represented the biggest danger. They have been blamed for most of the indiscriminate bombings--like the 1981 Bologna train station explosion that killed 85 people--that are considered part of a "strategy of tension" aimed at plunging Italy into civil war.

Leftist groups like the Red Brigades became more active after 1975. They were more selective than the fascists in their choice of targets, prefering individual assassinations, "knee-cappings" or shooting people in the legs, and kidnapings.

One of the brigades' early slogans was "The vote doesn't count; the rifle does." It captured the frustration felt by a large part of Italian youth with the country's inefficient parliamentary system, its frequent corruption scandals and ramshackle economy.

"In an individual, frustration produces a neurosis. In Italy, it produced terrorism. Urban crime in this country has always had a political character to it," Manconi said.

Other experts prefer a psychological explanation. One theory is that the rise of terrorism in Italy coincided with the breakdown of such traditional institutions as the Communist Party, the Roman Catholic Church and even the family. It has been suggested that young people who became terrorists were looking for new forms of faith and of devotion to a simple goal.

Franco Ferrarotti, a sociologist who taught several influential members of the Red Brigades, noted that many terrorists came from religious or Communist families. He detects in the terrorist movement both a distortion of the Christian myth that "the world can only be purified through bloodshed" and a rejection of the Italian Communist Party for "betraying the revolutionary struggle" by emphasizing parliamentary methods and criticizing Soviet efforts to dominate the world communist movement.

Senior Communist officials like Giorgio Napolitano insist that the psychological explanation is too glib. He says that left-wing Italian terrorism has to be put in an international context and traces its ideological origins to the Chinese Cultural Revolution and the exploits of Latin American guerrillas.

Napolitano believes that the underlying reason for the eventual defeat of terrorism in Italy was its "moral isolation" from the mainstream of the working class movement.

The terrorist phenomenon has left permanent marks on Italy. It introduced a sense of mutual suspicion and political intimidation into what was previously a very open society. The sight of carloads of armed bodyguards following a politician or businessman has become common in Rome and other major cities.

Some jurists say the antiterrorist legislation introduced in the late 1970s is likely to have a permanent impact on the Italian judicial system.