Cracks in Mafia code of silence hold key to crackdown in Sicily

''To eradicate the Mafia, you must remove the water in which the Mafia fish swims.'' Italian Mafia-fighter Carlo Alberto Dalla Chiesa is said to have made this remark not long before he was killed by the Mafia in September 1982. The ''water'' he was referring to is made up of longstanding distrust of authority, political corruption, and poverty in Sicily.

Although arrest warrants were recently issued for 493 Mafiosi, more than half of whom are now in custody, the water in which the fish swims is as deep as ever.

Sicilians' traditional distrust of authority takes the form of omerta - the code of silence in which there are never any witnesses to a crime. Everyone denies having seen anything, heard anything, or having any knowledge of anyone even remotely connected with the events in question. The widespread observance of omerta - nourished by a steady diet of fear - has allowed the Mafia to function in Sicily virtually unchecked.

Omerta has prevailed not only within the Mafia itself, but also among the poor of Sicily, who have looked to the Mafia to provide the security and the justice they have not received from the state.

Since Mafia boss Tommaso Buscetta's unprecedented ''singing'' to the police last summer - followed by that of lesser Mafiosi ''Totuccio'' Contorno and Salvatore Coniglio - the tradition of omerta ''has been weakened considerably,'' says prosecuting magistrate Giusto Sciachitano. Mr. Sciachitano has called omerta ''the greatest single obstacle'' in his investigations of Mafia crimes, but he hopes that Buscetta may have set an example that others, including private citizens, will follow.

However, the war against omerta may have received a setback, since the brother of Salvatore Coniglio was shot dead last week, presumably as a reminder of the consequences of collaborating with the police.

''The victims of Mafia crimes have never wanted to talk to the police,'' Sciachitano explains. ''But the more people begin to talk, the easier it will be for others to speak up, especially when they see that the authorities take action against the criminals.''

As the walls of omerta begin to break down, will the fundamental causes and conditions of the Mafia in Sicily be destroyed? Unfortunately, it is not that simple.

A twofold problem has produced the habitat in which the Mafia has thrived: the weakness of local government and public institutions - and poverty.

Padre Ennio Pintacuda, founder of Palermo's Center for Social Studies and professor of sociology at the University of Palermo, puts the problem in historical perspective.

''In the 19th century,'' he says, ''the colonial government of the French Bourbons, and later of the Piemon-tesi Italians, was so weak in Sicily that the aristocracy, who lived in the cities away from their farming estates, turned to the Mafia to keep order in the countryside.

''Even then, the Mafia was a criminal organization, but it was considered a lesser evil than the chaos and insecurity of anarchy. Even the (Roman Catholic) churchchose to tolerate the Mafia during the last century, because it in turn respected the authority of the church and the institution of the family, and because it did keep the peace in the countryside.''

Since the end of World War II, the Mafia has shifted its activities from the countryside into the cities. And its power has grown steadily as a result of the continued weakness of the state.

Luigi Cocilovo, regional secretary for Sicily of the labor union Confederazione Italiana Sindacati Lavoratori, says the root cause of the Mafia's strength in Sicily is poor government, or, as he puts it, ''nongovernment.''

''Politicians are not judged on performance,'' he explains. ''They are elected with the support of special interest groups. If a Mafioso asks a favor of a politician, the politician will grant it because the Mafioso has promised him a certain number of votes. It is not exactly that the politicians are in the pay of the Mafia, but the weakness of the political system opens them up to pressure from the Mafia.''

Perhaps the greatest irony of the present situation in Sicily has to do with what Giuseppe Insalaco, who was mayor of Palermo from April to August of this year, calls ''la nostalgia della mafia.'' It concerns a basic element of the ''water'' the Mafia thrives in: poverty.

La Vucciria, part of the historical center of Palermo near the waterfront, is a labyrinth of narrow, cobbled streets and crumbling, filthy buildings dating back at least to the 17th century. Large families often live crowded together in small spaces. Giovanna and her family are typical. She and her husband, Vincenzo , and their six children live in a single room. Vincenzo sells fried meat scraps from a wooden cart on the street. Giovanna used to work. Now she stays at home with the children.

The main problem for the people of La Vucciria, and for the many other poor sections of Palermo, is unemployment, which has grown to crisis proportions since the crackdown on the Mafia leaders began.

The Mafia provided jobs in the construction industry or in other small concerns where money made from the drug trade or from prostitution was laundered. Now this system has been suspended, and the people feel nostalgia for the Mafia.

''This is a precarious time for Sicily,'' ex-Mayor Insalaco says. ''If the Mafia is a problem of Italy and of the world, then Palermo deserves special attention. The government must come in with 'clean' money - public works projects to provide jobs. They must provide compensations to discourage illicit business. Otherwise the unemployed involuntarily become tools of the Mafia.''

The problems that have given rise to the Mafia in Sicily are easily defined. The vital question now is: What is being done to solve these problems?

In education, a concerted effort is being made to present the Mafia to children as an evil they can help to overcome. In 1980 legislation known as Law 51 was passed. It ''calls upon the schools of Sicily to foster a civic consciousness against Mafia criminality.'' This year, 1 billion lire ($533,049 at the current rate of exchange) was set aside for special projects in the schools connected with this anti-Mafia program.

Professor Pintacuda explains the unprecedented vigor with which, since around 1970, the Catholic Church has spoken out against the Mafia and against the problems of Sicily in general.

''In the Center for Social Studies,'' the Jesuit professor says, ''we have been speaking out against the Mafia since 1970. We plainly declared that the Mafia is a social evil, that it does not support social values. Palermo's Cardinal Pappalardo was receptive to what we were saying, and he moved to the forefront of the battle.''

In a recent television interview, the cardinal won the applause of many observers for the firm stand he took in denouncing the violence of the Mafia and the drug trade it has engaged in. The church is also involved in organizing clinics for the rehabilitation of drug users.

Leoluca Orlando is a young professor and lawyer who is encouraged by the church's involvement in the Mafia question. Mr. Orlando is considered to be one of a new breed of honest young politicians here who are committed to bringing about change. Recently he ran for mayor - and lost, reportedly because of his personal distance from the Christian Democratic Party he represented.

''If you go around the churches in Palermo on a Sunday,'' Professor Orlando says, ''you will see that they are all full. There has been a return to the church. People are beginning to see the church as a force for modernization. There are organizations within the church which are on the cutting edge of change.''

One such organization is called ''Una Citta per l'Uomo'' (A City for Man). Founded in 1982 in connection with Padre Pintacuda's center for Social Studies, this Catholic organization is dedicated to solving the problems of modern Sicily through increased participation in politics, either within the established Christian Democratic Party or as an alternative to it.

Una Citta per l'Uomo demands honesty in politics and encourages citizens to get involved in the issues of the day. As a political entity itself, it garnered 26,000 votes and five seats on the City Council in local elections in Palermo last May.

There is a growing realization here in Sicily that an improvement in the political picture - as well as a change in time-honored attitudes - is essential to the fight against the Mafia. So is the pumping in of public funds from the central government in order to alleviate the region's poverty and provide legitimate jobs, with local supervision of such programs to ensure that the funds are properly spent.

Without these measures, the ''water in which the Mafia swims'' - the poverty, political weakness, and observance of omerta - is likely to remain as deep as ever.