Who says Andropov's a liberal?

As Moscow's recent and unprecedented harassment of Marxist dissident historian Roy Medvedev vividly demonstrates, Andropov's accession to power will not usher in a new era of liberal political reform in the USSR. In fact, contrary to conventional wisdom, it was probably not Andropov but his rival, Konstantin Chernenko, who was the liberal reform candidate in the succession struggle.

Andropov's reputation as a liberal seems to have been most heavily promoted by members of Moscow's academic and cultural communities, who are reported to have benefited from the KGB chief's personal appreciation of artistic creativity and scholarly excellence.

But friendship with the research institutes and avant-garde theaters cannot change the essential realism, and even the brutality, of this man who headed the USSR's security police for 15 years.

During Andropov's tenure as KGB chief, psychiatric incarceration of human rights activists became standard practice, with the number of prison hospitals devoted to such treatment increasing accordingly.

As dissenters gained numbers at home and support abroad, the KGB chairman ordered his agents to throw legality to the winds: Firearms and narcotics were planted in the homes of some dissenters and trumped-up rape cases were built against others.

When such measures failed to subdue opposition, the security chief permitted subordinates like Vitaly Fedorchuk in the Ukraine to eliminate the more troublesome, or less prominent, dissidents and occasionally members of their families.

There is little indication that Andropov will lighten up now that he has been named general secretary of the party. According to the congressionally based Helsinki Commission, a recent amnesty of prisoners, announced on the occasion of the USSR's 60th anniversary, has been smaller and has included far fewer political internees than was the case in previous years. And there is certainly no lessening of the energy with which the KGB is repressing unrest in the Baltic states and elsewhere.

Andropov's proven record stands in some contrast with the policies his political competitor, Central Committee Secretary Konstantin Chernenko, has advocated in recent writings. As early as 1971 (well before his entrance into the lists of succession contenders), Brezhnev's protege began pushing for democratization of the Communist Party. Greater openness in decisionmaking, freer, less orchestrated debate in meetings, and a reduction in the traditional secrecy enshrouding the party's work have figured prominently in Chernenko-sponsored proposals for political reform.

The Central Committee secretary has also proposed forging more responsive relations between the party and Soviet society.

As the latter becomes better educated and more sophisticated, Chernenko has argued, the party should take greater care to reflect popular opinions in its policies. The failure to do so in Poland has, he believes, been a central cause of the crisis in government currently occurring there.

Chernenko's apparent populism may be part of the reason his candidacy has failed to gain widespread support among the Soviet leadership. Kremlin leaders are the products of a political culture which exhibits a deep distrust of pluralistic - and in the Russian view, potentially anarchic - methods of government. They are jealous of the prerogatives of the power they have earned and are paternalistic in their attitudes toward the appropriate role of government in society. Men such as these probably have little time for innovations which could challenge their political position or control, and they are undoubtedly fearful of changes which could undermine the shaky structure holding an increasingly undisciplined and apathetic Soviet society together.

The ''harebrained'' populist reforms foisted on the party faithful by Khrushchev are remembered with a good deal of distaste and the notion that the regime should become more responsive to the Soviet people seems to attract little enthusiastic support.

Indeed, in some circles, the perception may be growing that the average citizen has become unacceptably soft and needs a dose of stiff discipline to toughen him up.

In short, even if Chernenko as the liberal candidate had emerged victorious in the succession struggle, the limits to political reform would still have been quite narrow. Certain attributes of the system are not negotiable: Power must remain firmly in the hands of the party and opponents of the regime will continue to be given no quarter.

Moscow has been willing to compromise on some human rights matters in the past. Throughout the 1970s, the expectation of tangible trade benefits made Jewish immigration and the release of dissidents seem reasonable concessions to Western opinion. But today the Soviets are both less confident about their ability to contain dissatisfaction at home and more skeptical about the advantages to be derived from economic relationships abroad.

In the near term, the prospects for liberal reform thus remain dim.