Case of 'singing' Mafioso fails to impress Italians; But his breaking code of silence helps police begin to crack Mafia

''Il governo e mafia,'' said the blue-eyed high school student in Piazzale Flaminio. His remark echoed what a bank clerk in a residential section of Rome had said the day before, when asked his opinion on the latest events concerning the Mafia in Italy: ''The government is the Mafia.... Politics and the Mafia are the same thing.''

These statements, cynical and bitter as they may appear, were accompanied by knowing smiles and casual shakes of the head, as much as to say, ''Nothing surprises us Italians.''

After 40 years of constantly changing governments, of leaders who are better known for the scandals they are linked with than for acts of statesmanship, Italians are too worldly-wise to be greatly encouraged by isolated signs of progress where the uprooting of corruption is concerned.

The tangle of crime, greed, and violence that is exemplified by the Mafia and its alleged connections with political figures cannot be unraveled easily. In order to exist, Italians argue, a huge organization like the Mafia must operate with the knowledge, if not the actual support, of the authorities.

Nevertheless, during the last few days here in Italy, the signs of progress in this unraveling process cannot be ignored. For the first time in the history of the centuries-old brotherhood of outlaws, one of its bosses is talking to the police.

Tommaso Buscetta is naming names of fellow Mafi-osi, who he claims, are responsible for a long list of unsolved crimes. As the Italians put it, Mr. Buscetta is ''singing.''

To examine the reasons why he is singing is to begin to understand how the traditional Mafia has always operated as well as how it has recently changed.

The Mafia is a family affair. As on all levels of Italian society, family relationships in the Mafia are sacrosanct. In the last two years, Buscetta has lost two sons, a son-in-law, a brother, and a nephew - as well as many close friends - all shot by members of opposing Mafia clans.

Italians commenting on his recent revelations have asked, ''What more has he got to lose?''

Since Buscetta himself is in prison near Rome (having been extradited last July from Brazil, where he was in hiding), what better way to carry out his ''vendetta'' than to point out his enemies to the police?

But Buscetta's unprecedented ''singing'' may well be symptomatic of significant alterations in the very fabric of the Mafia itself. A university professor here in Rome explained the ''old'' Mafia as a highly structured society with a strict code of honor, in which the divulgence of ''family'' secrets to the police was unheard of.

Since the early 1970s, however, the international drug trade has been the Mafia's main source of revenue. The funneling of heroin and cocaine from South America and Asia, through clandestine laboratories in Italy and onto the streets of all the major Western cities, is big business.

The traditional Mafia has had to take into its ranks many independent criminals, and they often do not play the game according to Mafia rules.

In the current issue of the Italian magazine Oggi, Tommaso Buscetta himself is quoted as saying, ''... in the last few years, a tremendous process of degeneration has wreaked havoc with the rules which used to govern the organization: The traditional code, which as a man of honor I used to obey, no longer exists.''

At this writing, Buscetta has named 366 Mafiosi as being guilty of various crimes. Some 200 of these were already in Italian prisons, and at least 58 have been arrested in Italy since Buscetta started ''singing.'' Twenty-eight are presumed to be in the United States and authorities there have begun arresting them.

Many Italians are skeptical that Buscetta's revelations will lead to the arrest and imprisonment of the top Mafia leaders, and whether the Mafia's alleged ties with Italian politics will ever be brought into the open.

Piazzale Flaminio, where the skeptical high school student was standing, leads into the honey-colored Baroque expanse of Rome's Piazza del Popolo. In the shadow of one of its three magnificent domed churches is a chic restaurant-bar with tables on the piazza. One of the employees there, a grandmotherly woman named Caterina, seemed only too happy to pour her own tales of woe into the ears of a journalist.

''The thing that breaks my heart today,'' said Caterina, ''is drugs. They are destroying our young people. My son came home from school one day - he is 19 - and he said to me, 'Please take me out of that school. Every day there are men outside the school, and they tell us that if we don't take the drugs they have with them, they'll kill us.' Well, I took him out of that school, but what about the other young people who don't escape? What's to be done about them?''

Caterina may be fond of dramatizing, as many Italians are, and it is unlikely she is very well informed on political matters. But it is clear that when she thinks of the current political situation in Italy, she feels trapped. She puts little faith in Tommaso Buscetta's revelations, because to her, as to the blue-eyed student in Piazzale Flaminio, the Mafia and the government are linked. And apparently they are not the only ones who feel that way.

An article on the front page of the Rome newspaper Il Tempo entitled ''Can the Mafia be terminated?'' sums up in absolute terms the need of the hour: ''In order to destroy the Mafia ... corruption must be uprooted; life must be made difficult for those who would corrupt and for those who allow themselves to be corrupted.''