THE events of a year ago that brought down one communist regime after another in Eastern Europe are far from played out. As the past week illustrated, the transition to greater political and economic openness is unpredictable, and still potentially explosive. Bulgaria, whose ``revolution'' had little of the drama evident in other parts of the old East bloc, may be approaching a climax of sorts. A general strike has registered popular discontent with food and fuel shortages, and the Socialist (formerly Communist) prime minister has been forced to resign. This means the same men who pushed the former hard-line Communist government out are now themselves being thrust aside.
Next door, the loosening of old political bonds appears to be leading toward Yugoslavia's disintegration. A US Central Intelligence Agency report predicted that the union of Balkan states could come apart within 18 months and speculated that civil war was a possibility. Yugoslav Prime Minister Ante Markovic has himself warned that independence leanings in Serbia, Slovenia, and Croatia are contributing to ultimate breakup.
To the north, Poland's voters, participating in their first national presidential election, gave startling support to an expatriate businessmen who has been dubbed ``the candidate from Mars.'' Czech voters, in the first free municipal elections in 52 years, showed an equally startling leaning toward the Communist Party, giving it a second-place 17 percent of their vote.
In both cases the favorites still came in first: Lech Walesa in Poland (though a runoff is needed) and Civic Forum, headed by President Vaclav Havel, in Czechoslovakia. But the protest implicit in support for Poland's unknown candidate, Stanislaw Tyminski, and for the Czech Communists, was plain. Many people in both countries are frustrated by the dislocation caused by current economic reforms. Some may even miss the old days of assured, if repressive, ``stability.''
The turbulence in these countries and others in the region suggests that the revolutions begun a year ago could still turn very sour, and even violent. International diplomatic initiatives, economic aid, and an outpouring of shared expertise are critical to help Eastern Europe build lasting democratic and capitalist institutions. Events can't simply be allowed to take their course. That unguided course, at this point, would appear to be veering toward chaos.