East Bloc’s Return to Hard-Line Rule Feared : U.S. Policy: Huge social and economic problems of the newly liberated nations could push some away from freedom, analysts and policy makers say.

WASHINGTON —  Government analysts and Bush Administration policy makers are increasingly worried that the huge social and economic problems of the freshly liberated East Bloc nations could push some of them away from freedom and into the grip of new authoritarian regimes.

Senior Administration officials still ardently support the East Bloc reformers, but they say the process of democratization is so fragile it could fall victim to political fragmentation, aggravated by serious economic strains.

The result, they say, could be a blighting of hopes for liberalization and a return to autocratic--though probably non-Communist--governments in at least some of the former Soviet satellites.

“We’ve seen tremendous positive change in Eastern Europe, but now we’re beginning to focus on the problems,” a senior Administration official said Friday. “There are political instabilities. There are enormous economic problems. In short, there are tough times ahead.”

U.S. analysts view Poland as especially vulnerable--partly because its economy already is far worse off than those of the other, more-advanced East European countries such as East Germany, Czechoslovakia and Hungary, and partly because it has the most sweeping reform plan.

“In Poland, we see a wave of strikes barely two weeks after the introduction of a truly amazing economic program,” an official said. “If anything goes massively wrong, it is likely to be in Poland.”

If Warsaw’s sweeping package of reforms does not produce some improvement soon, government sources said, the Solidarity-backed government could falter and eventually lose power to the military, which historically in Poland has taken things into its own hands during times of major governmental crisis.

Such a move could thrust Poland back into the hands of an authoritarian regime for the foreseeable future, one senior official said. “You might see a situation like the one in Argentina,” said one well-placed East European expert.

While Poland is considered most critical, Administration officials and senior government analysts also cite difficulties in other East European countries. The current unrest in Romania is “troubling,” one official said. He called the situation in East Germany “unclear and confusing.”

The Administration may soon consider new aid packages for countries such as Czechoslovakia and Romania, where the fall of the old Communist regimes came too late to be included in the assistance approved by Congress last summer for Poland and Hungary.

As the Administration views the East European situation, the newly liberated governments can be divided into two major categories: Economically healthy countries--Czechoslovakia, East Germany and Hungary--and countries beset by potentially crippling problems--Poland, Romania and Bulgaria.

Here is a country-by-country rundown of Washington’s assessment of the situation in Eastern Europe:

* Czechoslovakia: At the “top of the list” of potential success stories among the East Bloc states. The Communist Party has been discredited and is in full retreat. The country has the necessary historical and cultural conditions to make its reforms work, and it lacks the bitter ethnic and nationalistic divisions that haunt some other countries in the region. It also has a highly skilled work force.

* Hungary: No. 2 on most lists, Hungary began its reforms long before other East European countries. It has a motivated work force and an emerging political system. The question: Will the previous Communist rule be replaced with a coherent government after the spring elections?

* East Germany: With a reasonably skilled labor force and a rich uncle (West Germany) next door to help with financing, East Germany has bright prospects--if it can get its act together politically. Right now, the Communist Party still is fighting to stay alive in the face of determined opposition.

* Poland: Warsaw has put together the most sweeping program for economic reform, but its economy also is in the worst shape. The big question is how far the Solidarity-backed government can push its austerity program without splitting the party and losing support.

* Bulgaria: So far, everything is moving in the right direction. But it will take longer--possibly a year--for the Bulgarians to rout the Communists from their government and perhaps even longer for them to begin getting their economy back into shape.

* Romania: A country without long-time democratic traditions, Romania needs prompt elections, but it may not be able to achieve that goal. Human rights is likely to be a major issue for several more months, possibly years.

As they assess the clouded future of Eastern Europe and grope for ways to bolster prospects for democratic governments and market-oriented economies, Administration officials continue to marvel at the Soviet Union’s decision to take a hands-off attitude when the anti-Communist upheavals began.

Officials said the United States has no evidence that the Soviet Union has been actively involved in the reform effort in any country besides Czechoslovakia. And even there, Moscow’s role was indirect: Soviet officials merely signaled that Moscow now regarded its 1968 invasion as a mistake.

Even in Romania, where Moscow had no love for the late dictator, Nicolae Ceaucescu, the Soviets were restrained in advance of his overthrow.

“The last thing the Soviets wanted was to get involved in a resistance movement that might fail,” one U.S. official said.