BUCHAREST, Romania -- For all but the last two weeks of this year, Communist Eastern Europe passed through one of the most remarkable political transformations in modern history, a massive upheaval that was accomplished with hardly a shot fired.

The peaceful nature of the process was all the more remarkable for the fact that Communists in Poland, Hungary, East Germany, Bulgaria and Czechoslovakia had either been installed or held onto power through four decades by either outright violence or systematic coercion.

The Czechoslovaks, who waited until almost the last, could not resist bathing themselves in Vaclav Havel's praise for their "gentle revolution"--an idea that probably gave the cautious Czechoslovaks more credit than they deserved but nevertheless managed to stand as a characterization for the whole year.

And then Romania happened.

There was no gentleness here. The ferocity of the fight that drove Nicolae Ceausescu into flight Friday and continued until his execution Monday was on a scale familiar to Beirut, not Eastern Europe.

The assistant health minister said Tuesday that confirmed casualties, for the whole country, stood at 746 dead and about 1,800 wounded. Most of the deaths are believed to have occurred in Bucharest, not the western city of Timisoara, where the revolution against Ceausescu's rule began. The early estimates of casualties in the tens of thousands were exaggerated, but were apparently an outgrowth of the vicious battle put up by Ceausescu's secret police unit, the Securitate.

Why was the Romanian revolution so bloody while the rest of Eastern Europe displaced the Communist monopoly on power so peacefully?

The two main reasons, as evident now as the rubble and blown-out buildings around Bucharest's Palace Square, are the Securitate and the iron grip with which Ceausescu held the country.

Ordinary people in Romania, not a veteran band of dissidents, started the demonstrations against the regime in a way similar to the street protests weeks earlier in East Germany and Czechoslovakia. The difference here was in the government response. The Ceausescu government believed, from the beginning, that raw force was the only reliable means of forestalling a collapse of the regime.

Compromise Doomed

In a way, Ceausescu was right. From the earliest changes in the East Bloc this year, which occurred in Poland, it was evident that once the Communists began to compromise with the opposition, they were finished. It was a principle enunciated by the 19th-Century political theorist Alexis de Tocqueville that no time is so dangerous for a repressive government than the moment when it begins to liberalize.

Ceausescu may not have been a devoted reader of De Tocqueville, but he took it as a matter of faith that no compromise was possible. In the last decade of his rule, when his regime became harshest, no quarter was ever given to the few dissidents in the country. Most of the best-known dissidents, such as Doina Cornea, a Cluj University professor, were watched incessantly or kept under house arrest. Lesser-known "subversives" were dealt with even more harshly.

When the demonstrations began in Timisoara on Dec. 16, the Securitate began to move into place. On Dec. 17, they began to act. Demonstrators--the exact number remains unclear--were shot down in the town square. That day and the next, 47 soldiers of the regular Romanian army were publicly executed by the Securitate for refusing to fire on the unarmed protesters.

Fired on Crowds

That action was an indication of what was about to come.

Beginning last Thursday, as the protest spread for the first time to Bucharest, the ruthlessness of the Securitate became even more evident, and Romania's struggle began to look more like a coup attempt in a Third World country.

On the other hand, what happened in Romania seemed even more irrational.

Last Thursday night, the Securitate fired on crowds of thousands in the Palace Square. It has never been clear how many died, but doctors estimated the number to be at least several hundred.

During the early morning hours, trucks were sent to the square to pick up the bodies, and the blood was washed off the cobblestones with fire hoses.