THREE DAYS AFTER the killing of Aldo Moro in Rome, gunmen threw a businessman named Pietro Fiocchi out of a car near Milan. Mr. Fiocchi had been kidnapped last November and was being freed, six months later, upon the payment of $800,000 in ransom. The gunmen were also businessmen, in a manner of speaking. They represent the purely commercial side of the brigandage that is now on the rise in Italy. Several days later, another gang of kidnappers freed a 13-year-old child named Elena Corti, upon payment of another ransom. They had held her since January.

Last year in Italy 76 people were kidnapped, one of whom was Mr. Fiocchi. So far this year there have been 19, one of them Mr. Moro and another Miss Corti. There's an important difference in styles of terrorism between northern Europe and Italy. In West Germany, a small and isolated organization can occasionally carry off a spectacular crime. In Italy, the political outrages are part of a tide of kidnappings and assaults that range from the revolutionary to the purely mercenary.

The breakdown of law enforcement tends, unfortunately, to be circular. One successful crime incites other people with guns to try the same thing. Demoralization among the police spreads. To reverse the deterioration requires vigorous political intervention by the national leadership. Something like that happened in this country in the early 1930s amidst a rising toll of bloodshed and political corruption due to organized crime. Americans suddenly stopped treating bootlegging as a joke, and racketeers as folk heroes. The national campaign against organized crime was never totally successful, but in a remarkably short time it made racketeering far less attractive - and, perhaps as important, less glamorous.

To do the same thing in Italy will be harder, because of mixture of radical motives and simple greed. But political terrorism is nothing new in European experience. Both France and Italy suffered a succession of anarchist bombings and murders in the 1890s; in Italy, they culminated in the assassination of King Umberto. That example is worth recalling because in both countries liberal democracy survived and grew stronger.

The results of last weekend's local elections in Italy have no direct bearing on national politics, but they certainly suggest strong support among the voters for a kind of law enforcement that does not now exist there. Is the present government capable of meeting that demand? The leading figures in Italian politics tend to be cautious to a fault, suspicious of strong administration. They are given to proceeding slowly and, preferably, by indirection. Now their constituents seem to be pressing them to take an uncharacteristic kind of action. The whole political development of Italy is at stake in these events. But it is equally correct to say that it all comes down to the enforcement of the laws against kidnapping.