FOR ITALY, the crucial thing now is the nation's answer to the murderers of Aldo Moro. If it is limited to verbal denunciations of terrorism, and perhaps a stiffening of police protection for public figures, the social deterioration of Italy will continue. But it is at least possible, surely, that this horrifying crime may impel the country toward a more effective, more responsive style of politics and government.

The primary purpose of the Red Brigades was not to free their jailed confederates, or even to do away with Mr. Moro as an individual. It was to demonstrate the incompetence of the democratic Italian state and to demoralize its people.The attempt at public demoralization has failed, despite the enormous strain on the country.

But in all the melancholy catalogue of recent political crimes, it is difficult to think of a murder more terrifying in its manic calculation, or more curel in its deliberate degradation of its victim. Over the 55 days in which they held him, the kidnappers forced him deeper and deeper into psychological breakdown, advertising the stages of their progress by publishing his increasingly distraugt and desperate letters and appeals. Mr. Moro's captors chose him as the symbol of the state and destroyed him slowly, in a peculiarly gruesome example of political theater.

It is difficult to speculate on the atmosphere that might be running in, say, the United States if an American politican were seized and, after seven or eight weeks, the police still had no idea where he was being held or by precisely whom. The mood in Italy is, apparently, somber but certainly not hysterical. Italian society is a great deal more stable under tension than the Red Brigades like to think. But it is important to note some of the other things that have been going on since March 16, when Mr. Moro was kidnapped.

Two days later, in the face of endless threats, a court in Turin resumed the trial of a group of terrorists arrested earlier. Four days after that, gumnen of the Red Brigades shot they mayor of Turin, deliberately not killing him but aiming for his legs. In April, the same groups shot a Genoa businessman the same way, then assassinated one prison guard in Turin and another in Milan, wounded a politician in Rome and an executive of the Fiat automobile company in Turin. Last Thursday, in Milan and Genoa, they shot and wounded two executives of state-owned businesses. The purpose of this campaign was, presumably, to show that they could go wherever they pleased and assault whomever they chose.

What about the police? Countries with much tighter law enforcement than Italy have had great trouble controlling street-level terrorism. But, for political reasons, Italy's police have special weaknesses. The country went throuhg 20 years of fascism, and in the postwar years it chose to keep its security forces weak and fragmented. The curious thing about Italy is that, unlike the other powers of Western Europe, Italy persists in the postwar style of administration 33 years after the war. Worse, its governments have come to depend increasingly on pure patronage to stay in power. As the Communist Party gets closer to the government, places have to be found for its hangers-on. Constitutional weakness in the police is now being aggravated by old-fashioned jobbery.

There is going to have to be reform - but a reform that began and ended with the police and the criminal courts would be a decidedly sinister prospect. What about the other social services - particularly the schools and universities, the deterioration of which feeds the radical organizations? What about the poverty of the hospitals, and the housing shortages.?

To its great credit, the Italian government remained absolutely firm in its refusal to bargain with the terrorists. Despite the bloody outcome, that decision was right. Other European governments have tried to make deals in other cases, and almost always they have come to regret it bitterly.

But now the time has arrived for furthers answers to the Red Brigades.They have told Italians that the only choice is between ineffectual democracy and the radical's style of totalitarianism. Most Italians understand perfectly well that it's a false choice. But the demonstration requires a government capable not only of curbing the gunmen but of guarding and advancing the broader interests of its citizens. Mr. Moro devited his life to defending the democratic tradition in Italy. To strengthen and enlarge that tradition is the commemoration that his appalling death requires.