THE Christmas scene here provided an eloquent pointer to just about the biggest of the Communists' miscalculations spelling their downfall in Eastern Europe - their 40-year denial of the individual's freedom to travel. Almost four decades ago, Yugoslavia's Josip Broz Tito recognized the political safety outlet this particular human right could provide.
That largely explains why his Communist Party could still rule almost as autocratically as any, and only now - after the East Europeans - is forced to talk about multiparty elections.
The weekend before Christmas, central Vienna around Stephansdom Square was packed with Czechoslovaks. It was as if one of the massive demonstrations in Wenceslas Square against the Prague regime had been lifted here en masse.
Unlike the earlier East German exodus passing through Austria to West Germany, these Czechs were not in transit. They were visiting to savor being free and to ``see.''
``I haven't any money,'' a young woman told me perfectly cheerfully. ``But I'm free now to travel, that's the big thing. I will be quite content to take a coffee and a good look round before going home.''
Few of the visitors had more than 200 Austrian schillings ($16.60). But it seemed not to bother them in the least as they gazed into brilliantly lit shop windows for the affluent on K"arntnerstrasse and Graben.
Young and old alike gave the same impression of ``feeling good'' just because they were free to visit somewhere which, though so near their own borders, had been a virtually prohibited area for them for so long.
They didn't want to talk politics, or what comes next in Prague. ``I can think of that back home, for now I want to see everything I can here,'' was a typical response.
Back home, a no-longer-monolithic Communist Party was trying to salvage some of its shattered reputation. The parties in Poland, Hungary, East Germany, and even Bulgaria are all trying to do the same. Their prospects are not rosy.
Romania has avoided reform, though recent antigovernment demonstrations prompt the question: ``For how long?''
Elsewhere, one by one, the fundamentals of Communist power are being demolished.
The Polish, Hungarian, East German, and Czechoslovak parties have all abrogated the ``leading role'' of the Communist Party. They have conceded free, multiparty elections. They have changed names or are in the process of doing so.
All, in fact, are embarked on major public relations exercises combining suitable mea culpa to live down the awful past with pledges to behave democratically in the future.
It is doubtful how successful this bid for ``respectability'' and credibility will be, or if it can succeed. People have long memories.
Hans Modrow, the East German premier, forecasts Communists can expect only 20 percent of the vote in free elections. Elsewhere, the most optimistic comrades talk of but 30 percent.
The Czechoslovak party just announced itself open to readmission of the 500,000 members excluded by the Husak regime.
Only just over 100 applied at the same time as 40,000 handed in their party cards.
After 40 years of suppression, old parties that are now reviving themselves or new ones that are forming lack experience and need time to organize. ``New'' Communist reform parties may profit momentarily from these weaknesses. But credibility in terms of winning an election will be elusive for a long time. The best thing they can do probably is to apply themselves to the role of ``constructive opposition,'' which they had vetoed for others for 40 years.
It will test both their ability to change - and their sincerity.