ROME — Italy is painfully familiar with left-wing terrorism but now is facing up to an equally dangerous but little-understood phenomenon: terror on the right.
The latest incident for which neo-fascist rightist terrorists have been blamed was the bomb blast aboard Train 904, the Naples-to-Milan express, as it raced through a 12-mile tunnel in the Apennine Mountains between Florence and Bologna on Dec. 23. Fifteen people were killed.
Who are these rightists? Why do they plot such indiscriminate mass killings as the attack on Train 904 and the waiting-room bombing of the Bologna railroad station that took 85 lives in August, 1980? What do they want?
To Italian authorities, the last question is the easiest to answer. The terrorists want a return to rigid and orderly rule by a fascist elite over a nation that the extreme right believes has become hopelessly disorganized and frustrated under democracy. The name of a right-wing terrorist group that surfaced briefly a few years ago is an answer in itself: Mussolini Action Squads.
But in the twilight world of what the Italians call "black terrorism"--as distinguished from the more familiar red variety of the leftist Red Brigades--so little is known that even expert investigators who have spent months searching for subversive rightist groups and interrogating arrested fascist terrorists have had to call on political scientists and sociologists to test the logic of their findings.
For example, two Florence investigative magistrates, Pier Luigi Vigna and Rosario Minna, have spent much of the past year listening to jailed terrorists, some of them eager to cooperate, and compiling masses of information from police files. They then called in a political-social research group headed by Prof. Luigi Pedrazzi of Bologna University to sift the evidence for possible motives behind the bombings.
The Pedrazzi group studied the testimony of imprisoned right-wing terrorists such as Sergio Calore, who was convicted in the 1976 murder of an anti-fascist judge, and two self-proclaimed members of the most famous and most shadowy of the right-wing groups, the Armed Revolutionary Nuclei. The researchers drew a distinct contrast between terror from the left and terror from the right.
"To strike in a crowd has always been a characteristic of black terrorism, as opposed to the left-wing terrorism which has always chosen as its targets discrete symbols," they said.
The logic of indiscriminate attacks in which dozens of innocent people may die and hundreds may be injured, they said, follows the political logic of fascism, in which "the others" are different from the elite "us," and therefore are the enemy.
"The 'others,' " they quoted Calore as saying, "are only enemies to quash. In this sense, the massacre represents normalcy in neo-fascist politics. Whether this is accomplished verbally or materially, the aim is to deny those who are different from 'us' the right to existence."
The investigators and social scientists also came up with documentary evidence that disclosed why the right-wing terror groups have appeared to concentrate on bombing trains. Since 1975, at least 10 bombs have been planted on trains running in and out of Florence, four of them on the same line as Train 904. An earlier bombing, in 1974, involved the express train "Italicus" and left 12 dead, also at holiday time, near the tunnel where 904 came to grief.
In sifting through the papers of a convicted right-wing terrorist named Mario Tuti, whose Ordine Nuovo (New Order) is believed to be responsible for some of the worst actions, the investigators found a 30-page document spelling out the strategic value of blowing up Italian trains.
"Italy, like South America, presents the physical and social conditions suitable for the development of revolutionary guerrilla warfare," the document began. "The national territory is crossed longitudinally by an uninterrupted chain of mountains . . . . It is easy to look to the interruption of rail communications through the two crossings of the Apennines by way of sabotage of bridges, viaducts and tunnels, thus achieving the economic paralysis of the state . . . . "
Another specialist in terrorism, Prof. Sabino Acquaviva of Padua University, said that despite the rightist groups' appearance of structure and organization, they are small and not well organized.
"They have a less cultural and educated recruiting ground," Acquaviva said. "The leftist terrorist groups had a strong political and theoretical base, but the rightists have little or no cultural appeal, and for this reason they have made little progress."
If Acquaviva's assessment of the membership of the groups is correct, then it would appear from police and Interior Ministry statistics that the authorities have made deep inroads into their ranks. According to the ministry, almost half of the suspected terrorists arrested in 1983 and 1984 (146 out of 317) were neo-fascists.