MOSCOW, JUNE 24 -- Not long ago, Alexander Tsipko was a committed member of the Soviet Communist Party, a well-regarded Central Committee aide working under reformist Politburo members Vadim Medvedev and Alexander Yakovlev. Now he has all but given up on the party.

"I'm at a loss," he said. "I'm ready to quit."

Tsipko has watched a stream of provincial party hacks, disgruntled generals and other Communist fundamentalists level attacks at Mikhail Gorbachev for various transgressions against the old socialist faith, and he despairs of what could happen at next week's crucial 28th party congress.

Gorbachev himself was so frustrated with the authoritarian tone of Russian party members at a conference last week that at one point he said: "All that's left is for someone to say, 'OK, let's line them up against the wall!' "

Said Tsipko: "If these {hard-line conservatives} really unite, there is always the threat of a return to a totalitarian regime. That would be the ultimate disaster. At best, it seems, the party will have to keep compromising with its past. The Old Guard has no one capable of intellectual thought, no one who can think in political or economic terms. All they do is play on passions and a bogus patriotism. It's our tragedy, the people who haunt us."

For Tsipko and other members of the radical-reform wing of the party, known as Democratic Platform, the dream of transformation has a simple geometry -- that Gorbachev will make common cause with them and abandon the Old Guard once and for all. "The logic of life demands that Gorbachev unify with the most progressive forces in the party," Tsipko said. "But does he have the strength to make the leap? We can't wait a generation. The laws of development dictate that we make certain leaps of consciousness -- quick, decisive leaps. The experience of Eastern Europe shows that if you bog down on the path to reform, you can get lost. Sometimes you have to jump."

But so far it appears that Gorbachev -- a product of the Communist Party, after all -- feels he must stay within certain strategic and ideological bounds and seems content to push the party in the direction of reform while absorbing criticism from conservatives. The price of that strategy, if it continues past next week's national party congress, will likely be the defection of people like Alexander Tsipko.

Since the death of Stalin in 1953, splits in the Soviet Communist Party, small or large, have been a matter of secrecy. Even in the darkest moments of Leonid Brezhnev's attempt to revive the Stalin cult in the late 1960s, there were reformists and centrists in the party, a small current of official dissidence. Gorbachev's rise to power was the triumph of that reform current.

Over the past five years, Gorbachev has "retired" or discredited numerous Old Guard leaders and overweening party chieftains, including the two members of the party's ruling Politburo who challenged him for party leadership in 1985, Viktor Grishin and Grigori Romanov. In their places, Gorbachev elevated men like Yevgeny Primakov and Alexander Yakovlev, party academics and intellectuals who rode out the Brezhnev years at various policy research institutes and overseas embassies. Even the rector of the august Higher Party School, Vyacheslav Shostokovsky, is a radical reformist and leader of Democratic Platform.

Tsipko is a party intellectual who took Gorbachev at his word. At 48, he is 11 years younger than the Soviet leader, and he has been willing from the start to reexamine the history and possibilities of the ideology that shaped his life and career, challenging the Marxist-Leninist canon with a new irreverence.

A year and a half ago, Tsipko shocked his colleagues at the party's policy-making Central Committee with a four-part series of articles on the origins of Stalinism. Previously, most liberal academics had concluded that Stalinism was a murderous distortion of the promise of Lenin and that if Nikolai Bukharin, a champion of a mixed economy and a slower path to socialism, had won the political power struggle after Lenin's death, millions of people might have been spared the purges and artificial famines of the Stalin era.

In his articles in the journal Science and Life, Tsipko took a more heretical stance, arguing that the sources of Stalin's Great Terror are to be found not only in the dictator's own pathological behavior, but also in the Red Terror that followed the Bolshevik Revolution and, most of all, in the Marxist credo itself. At the root of the repression and slaughter ahead, Tsipko contended, were Marx's "false blueprint" for a dictatorship of the proletariat and Bolshevik insistence on applying a theoretical abstraction to a poor, peasant society.

Marxism had simply failed to understand the nature of human impulses, he wrote. "All our absurdities stem from our dogged refusal to see man as he really is, as he has been created by nature and history," and the Bolshevik abolition of private property led not to comfort and peace, but rather to "a crisis of labor motivation such as the world had never seen before.

"When the ideas about the goals of socialism are wrong," he continued, "when they contradict the laws of normal civil life, it is useless to argue about the pace or methods by which they are achieved. When you are dealing with a unrealistic goal, it does not matter whether you try to achieve it gradually or by using a cavalry -- the result will be the same."

Tsipko's articles were published uncensored, and he later delivered a lecture on his critique of Marxism to 300 colleagues in the international department of the Central Committee. The reception on both occasions, he said, "was a respectful silence."

"The fact is," he said, "no one denounced me. In fact, my personal position even improved. I was entrusted with more serious assignments. I know it is hard for people to believe, but the Central Committee apparatus is staffed with serious, intellectual people. They understood what I was talking about very well. Look, I just wanted to speak my mind, to be an honest man. There was no reprimand."

Last year, Tsipko left the Central Committee staff to become assistant director of the Institute of the Economics of World Socialist Systems, a wellspring of some of the most innovative economic research in Moscow. In recent weeks, Tsipko has published a number of articles and interviews in which he argues that the only way to build a social democracy in the Soviet Union is through creation of an economic system similar to Western capitalism. Before thinking about how to distribute social services, he says, the Soviet Union must first create a foundation of essential economic structures, a foundation of wealth and development.

For Tsipko, the only means of building a successful economy is "through the preservation of the entrepeneurial spirit and the creation of both private ownership and social guarantees." After meeting with a member of the French Socialist Party, Tsipko was beside himself. "It's funny," he said, "but my French colleague doesn't even think about the need for first creating wealth. It's no problem to him. To him it's just there, like the presence of air. In my country, people have to learn to work all over again. We have to have the courage to make the principle of private ownership untouchable. We've paid too high a price for our old battles against private property."

Unlike some radical reformists who believe that Gorbachev has reached the limit of his flexibility, that he can never completely reject the Communist Party culture and milieu, Tsipko still waits "for a miracle." Against all odds, he waits for Gorbachev to "show his true self" and join, once and for all, "his natural allies." The party "has to take a position somewhere between social democrats and liberals," or it is lost, Tsipko said, and to do so, he said, Gorbachev has to take yet another political gamble.

"So far, Gorbachev has been the key to solving all our problems," Tsipko said. "I'm not sure I can imagine my own political life without Gorbachev. I'm waiting for him to make that leap."