INSIDE the baroque Lucerna Dance Hall, long-haired youngsters swing to the incessant beat of loud music and acid lyrics such as, ``Skinhead, Skinhead, Bang! Bang! Bang!'' ``A few years ago, I was thrown in jail for promoting such music,'' marvels Karel Srp, the ebullient leader of the outlawed Jazz Section. ``It's progress, it's glasnost [openness] - but limited progress, limited glasnost, nothing like in Hungary or Poland.''
Czechoslovakia is trying to change. Long a leader of East European resistance to Soviet leader Mikhail Gorbachev's reforms, its orthodox communist regime now is buffeted by new pressures, from East and West, and from below. As the Lucerna rock concert shows, the hard-line leadership has responded by allowing more independent cultural activities.
But diplomats, dissidents, and even Communist Party functionaries doubt the depth of Czechoslovak glasnost. Official reform efforts remain defensive, they say, marked by caution and repression, while unofficial pressure from the long-passive population remains too weak to force an acceleration.
``The changes here just aren't systematic. They don't touch the roots of the totalitarian abuses,'' says one Western diplomat.
``People are bitter, but still not optimistic, and until they become optimistic, I don't believe they will be able to force reform on the authorities.''
This conclusion suggests some staying power for East Europe's hard-line bloc: Bulgaria, Romania, East Germany, and Czechoslovakia are all are resisting Soviet perestroika [restructuring] and glasnost. The so-called ``Gang of Four'' appears tentative, on the defensive. But it will be some time before these hard-liners start dancing to Gorbachev's tune.
Among this group, Czechoslovakia represents a crucial test case. Unlike Bulgaria, it boasts a strong democratic and industrial tradition. Unlike Romania, it is not ruled by a ruthless autocrat like Nicolae Ceausescu, who is willing to resist reform by starving his own people. And unlike East Germany, whose status as part of a divided nation makes any change potentially destabilizing, Czechoslovakia does not oppose the Soviet Union - at least not publicly.
``The East Germans say, `We know what we're doing; we don't need perestroika,'' explains Jaroslav Jiru, a journalist at the underground Lidovie Noviny magazine. ``Our leaders say, `We need perestroika, but we must be careful, and do it our way.'''
Communist Party leader Milos Jakes epitomizes this cautious perestroika. After the 1968 Soviet invasion, he directed the purge expelling almost half a million people from the party. University professors were turned into window washers, engineers into stokers, and lawyers into taxi drivers. Now Mr. Jakes is trying to shed his image as a colorless apparatchik.
In recent months, he has ousted hard-liners in the ruling Presidium and even taken to Gorbachev-style street chats. But at the same time, he expelled the Presidium's leading reformer, Lubomir Strougal.
``Jakes must go. He is impossible,'' says Jiri Dienstbier, a leading dissident. ``Whenever he tries to play Gorbachev and go out on the street, he talks nonsense and people laugh.''
Attempts to bridge the division between officials and the opposition have deteriorated. In December, the regime moved to silence criticism of its record on human rights by naming its own human-rights committee and authorizing it to make contacts with independent organizations such as the Charter 77. (See sidebar.)
Some meetings were held, but to no avail. The officials insisted on treating Chartists as private individuals, not members of an organization. The Chartists declined, fearing a ploy to co-opt them. Even after dissident writer Vaclav Havel was released, they still complain about a rise in politically provoked harassment and jailings.
``The idea of this official human-rights group was to divide us, into those for and those against cooperating,'' argues a bitter Peter Uhl, a leading Chartist. ``Worst of all, we saw that it had no real power to make decisions. We still count more than 100 people in prison on political charges.''
Official half steps and hesitations also mark the cultural thaw. According to Josef Simon, editor-in-chief of Odeon Publishers, the official Writer's Association has decided to return books by more than 200 banned authors to libraries this fall. But despite rumors that the works of famed 'emigr'e novelists such as Milan Kundera and Josef Skvorecky soon would be released, Mr. Simon says that such a decision still remains far off.
``It's going to be a gradual process. Most of the [unbanned] books are by dead authors,'' he says. ``We still don't have the courage to start dealing with the live authors.''
This lukewarm glasnost puts Prague in almost constant conflict with its more adventuresome neighbors. When Poland's Prime Minister Miecyzslaw Rakowski attended the opening night in Warsaw for a performance of Vaclav Havel plays, all of which are banned here, the Czechoslovaks issued an official protest. Earlier this month, Hungary shocked its neighbors, first by stopping work on an expensive joint project to dam the Danube River, and then by showing a television interview with Alexander Dubcek, the ousted leader of 1968 Prague Spring.
``Poland and Hungary are going through a political crisis,'' judges Milan Jelinek, foreign editor of the Communist Party daily Rude Pravo. ``We want to take concrete small steps, to reform socialism, not destroy it.''
The only real formula which will convince skeptical Czechoslovaks that their rulers are serious about change would be the rehabilitation of the hundreds of thousands of capable people who found their careers ruined after 1968. That means Gorbachev must admit that the Soviet invasion was a mistake. So far, the Soviet leader has backed away from taking such radical action, supporting the stability of the status quo over than the uncertainty of a rapidly reforming Czechoslovakia. If his preference changes, Czechoslovakia also could change - fast.
``Sooner or later, the question of the Soviet invasion will be opened,'' Vaclav Havel predicted following his release from prison. ``Our leadership, which bases its legitimacy on this invasion, will crumble once that happens.''