IN THE MORNING hours of July 7, 1992 an unusual spectacle unfolded in the center of Moscow, off Staraya Ploshchad, where until recently the all-powerful Central Committee of the Communist Party of the Soviet Union (CPSU) had had its headquarters: In a small room, 13 magistrates sat in judgment on both the democratically-elected government of President Boris Yeltsin and its predecessor, the CPSU.

The event had no precedent in Russian history, for Russia's governments had always stood above the law. Watching the proceedings of the Constitutional Court, one had the sense of witnessing a dramatic break in the destiny of an ancient nation that had suffered more than most from the curse of lawlessness.

The antecedents of the trial go back to the abortive putsch launched one year ago by a group of Communist officials, military officers and functionaries of the security services. Its immediate purpose was to prevent the signing of the new federal constitution, which would have deprived them of much authority. Ultimately, it was intended to put an end to perestroika, which they felt had gotten out of control. They organized their coup badly and when Yeltsin, supported by a few thousand brave democrats, stood up to them, it collapsed.

Three days later, Yeltsin issued a decree in which he accused the CPSU of direct involvement in the coup attempt. Hearings followed. On Nov. 9, 1991, Yeltsin issued a further decree which asserted that the CPSU "was never a party" but "a special mechanism for the creation and realization of political power through fusion with state structures or their direct subordination" to itself. The decree accused the CPSU not only of masterminding the putsch but continuing to undermine democratic institutions with the view to staging another coup d'etat. The CPSU was ordered to cease all activity on Russian territory and to turn over its properties to the state. The decree explicitly forbade prosecution of individual citizens for membership in the outlawed party.

Following this, 37 peoples' deputies representing the defunct CPSU petitioned the Constitutional Court to review the decrees for alleged violations of several articles of the republic's constitution. A group of anti-Communist deputies responded with a countersuit, charging the CPSU with being an unconstitutional organization. The two suits were tried concurrently.

I happened to be in Moscow when the trial opened, doing research in the Central Party Archive that Yeltsin's decrees had at long last made available to scholars. The Constitutional Court invited me to judge the premises underlying the decrees -- in particular two key questions: "Can one regard the CPSU as a political party?" and "Has the CPSU committed some violations of the Constitution, of laws and norms of international law which give grounds for regarding it as an unconstitutional organization?"

I agreed to serve as expert witness on a subject to which I have devoted many years of study. I did not take seriously warnings by some friends that this carried physical risks: It came something of a shock, therefore, to learn a few days later that Sergei Shakhrai, President Yeltsin's principal spokesman in the court, was nearly killed in a road accident that had all the earmarks of an assassination attempt.

Because of schedule conflicts, I recorded my views in a written deposition, confirming as historically sound the premises of the presidential decrees concerning the nature and operating methods of the CPSU: The Bolsheviks from the day of their October 1917 coup d'etat acted not as a party but as a state-within-the state, banning every rival political organization and taking all decisions affecting the government within the narrow confines of the Bolshevik Central Committee and its Politburo. Since disbanding the Constituent Assembly in January 1918, they behaved in an indisputably unconstitutional manner.

Nothing that I wrote was new. But in Russia, where for 70 years the CPSU had monopolized the historical sources as well as the writing of history, what is obvious to Western specialists can come as a revelation. The trial opened in an atmosphere charged with tension. Outside the courtroom, behind barriers set up by the militia, crowds of Communist sympathizers, their faces distorted with anger and hatred, demanded to be allowed in. They clearly wanted to disrupt the proceedings. I could not help thinking that but a year earlier, the roles would have been reversed: the stony-faced militia would have kept behind barriers, if not behind bars, the very persons they were now protecting.

Inside the court, one Communist representative threatened a new coup, for which he was reprimanded by the Chief Justice Valerii Zorkin and barred from further testimony. When a judge announced my name as a court-appointed witness, a Communist deputy sprang to his feet to protest a foreigner being called to testify at a Russian constitutional trial. To this, Zorkin replied that the court was free to choose as its expert any one it thought fit.

From long habit, the Communists, impeccably dressed and groomed, sitting in a phalanx to the left of the judges, behaved as if they were still in charge. They reminded one of nothing so much as of an ex-boxing champion who had suffered brain injury and could no longer fight but, unaware what had happened to him, flexed his muscles and offered to take on all comers. They were a pathetic lot.

The proceedings had about them an air of unreality, symbolized by the hammer-and-sickle hanging in the rear of the courtroom side by side with the Russian tricolor flag. Nine of the 13 judges are said to have belonged to the Communist Party.

It is not clear how the CPSU can be prosecuted under a constitution of its own making (and still in force). The Communists' appeals to law, the separation of powers and the principle of political pluralism are plainly ludicrous. At every step there is evidence of inexperience, lack of precedent and, despite earnest attempts, of an inability to keep politics separate from law. The public, which has never known legal standards to be applied to its government, is receptive to arguments of Communists that the proceedings are a Russian version of the Nuremberg trial and that the CPSU is tried not for having done anything wrong but for its having lost out in the struggle for power.

But whatever the verdict on the Communist Party, the constitutional trial now in progress (it adjourned at the beginning of August for one month), is of great historic significance, and this for two reasons:

Russia never went through a feudal period, in the true sense of that word, and hence is unfamiliar with the fundamental precept that lord and vassal are equally subject to contractual obligations, that is, to legal norms -- a precept later extended in Western democracies to relations between government and citizens. Not only czarist governments but even czarist officials enjoyed exemption from legal culpability. During the brief constitutional period (1906-1917), czarist ministers could be questioned in parliament about illegal acts attributed to them but they could not be removed from office, let alone tried.

As for Lenin, he made no secret that he regarded law as an instrument of government: He defined the "dictatorship of the proletariat" as authority unconstrained by law. And he constructed on this principle a pseudo-judiciary system that Stalin inherited and perfected. In the entire history of Russia, and especially during the Communist reign, lawlessness was not simply a fact of life in the relationship between state and citizenry but an institutionalized principle, the quintessence of the system.

This pernicious tradition is now being breached. No matter what the outcome of the trial, the principle has been established -- and this, paradoxically, as a result of a suit initiated by the Communists themselves -- that government, like a private citizen, is subject to law. It is the first step on the road to civil society and the creation of a constitutional framework without which no progress, least of all economic progress, is possible.

Secondly, the proceedings are likely to provide Russians with an unforgettable lesson in their own history. Presidential experts, gathering evidence for the trial, have been allowed into the most closely guarded archival repositories of the CPSU and its agencies, including the KGB. Much seems to have been destroyed, but dozens of volumes have been compiled to serve as evidence of the party's criminal activity. The public, of course, is vaguely aware that terrible things have happened in Russia since 1917, but it has been influenced by the self-serving claims that the cruelties had been necessary to prevent counter-revolution and foreign conquest.

When the trial resumes and the spokesmen for the president have the floor, they will learn the full dimensions of the barbarities that had been committed to no other purpose than to keep the Communists in power. The KGB has already been forced to reveal that the Soviet regime executed 828,000 persons for so-called anti-state crimes, a figure that represents only a fraction of the millions who had lost their lives without being formally sentenced to death as a result of police-inflicted and police-supervised beatings and malnutrition. As the presidential party unfolds its case, the majority of the citizens will, for the first time, have the opportunity to learn what their parents and grandparents lived through and what censorship and fear had concealed from them. The importance of this lesson in history cannot be overestimated. It is likely to have an enormous cathartic effect.

Everything in Russia is in flux. The trauma of Communism, still inadequately appreciated in the West (in no small measure thanks to years of soothing disinformation dispensed by fellow-travellers and "value-free" social scientists), had created in the majority of the population, especially among the better educated, a revulsion against the past. They are thoroughly rid of the old national arrogance and of the messianism that gave it political expression. They suffer under the weight of guilt and inferiority that the Communists seek to turn to their own advantage by denying they have anything to be ashamed of.

But there is no return for the Communists. Even if they toppled the democratic government and reclaimed dictatorial authority, they would be able neither to solve the basic problems that afflict the country nor frighten the population into total submission. The defense of Moscow's White House last August was the first step on the road to a new Russia; the constitutional trial is its logical resolution. There is hope. Richard Pipes is Baird professor of history at Harvard and author of "The Russian Revolution" (Vintage). In 1981-82 he served as director of East European and Soviet Affairs in President Reagan's National Security Council.